• Chemical Causes of Permanent Hardness in Water:
• Temporary Hardness (Carbonate Hardness): Caused by dissolved bicarbonates of calcium and magnesium: $\text{Ca(HCO}_3)_2$ and $\text{Mg(HCO}_3)_2$, removable by simple boiling.
• Permanent Hardness (Non-Carbonate Hardness): Caused by dissolved chlorides and sulfates that cannot be removed by boiling:
• Calcium sulphate (CaSO$_4$)
• Calcium chloride (CaCl$_2$)
• Magnesium sulphate (MgSO$_4$)
• (along with Magnesium chloride, MgCl$_2$).
• Conclusion: (C), (D) and (E) only (Option 4).

Correct option: (4) (C), (D) and (E) only.

• Match Yarn Texturizing Processes with Structural Effects:
• Knife edge texturizing $\longrightarrow$ (II) Spiral coil like: Filament yarn is drawn across a heated sharp metal edge, inducing asymmetric differential shrinkage that produces helical spring-like coils.
• Stuffer box crimping $\longrightarrow$ (IV) Saw tooth crimping: Filaments are rammed rapidly into a heated confined chamber, folding yarns into sharp zigzag/sawtooth crimps.
• Air jet texturizing $\longrightarrow$ (I) Loops and curls: Cold supersonic turbulent air jet blows filaments apart, forming randomly entangled surface loops without heat setting.
• Knit-de-knit texturizing $\longrightarrow$ (III) Very pronounced loop / crinkle structure: Filament yarn is knitted into a tight fabric tube, heat-set, and unraveled to impart crinkle crimp.
• Conclusion: (A) - (II), (B) - (IV), (C) - (I), (D) - (III) (Option 3).

Correct option: (3) (A) - (II), (B) - (IV), (C) - (1), (D) ~ (ttl)

• Textile Classification: Velvet vs Napped vs Flocked Fabrics:
• Assertion (A): Velvet is a napped fabric. $\implies$ Incorrect.
• Velvet is a warp pile fabric constructed with an extra set of warp yarns forming upright loops that are subsequently cut to produce a dense upright pile, whereas napped fabrics (e.g., flannel) are plain or twill fabrics brushed with wire rollers to raise existing yarn fiber ends.
• Reason (R): It is produced by attaching very short fibers to the surface of the fabric. $\implies$ Incorrect.
• Attaching short chopped fibers (flock) to an adhesive-coated fabric substrate using electrostatic charge is called flocking, not pile weaving or napping.
• Conclusion: Both (A) and (R) are incorrect (Option 2).

Correct option: (2) Both (A) and (R) are incorrect

• Cross-Dyeing and Solid-Shade Dyeing of Fiber Blends:
• Assertion (A): It is possible to dye textiles containing fibres having different dye affinity, with one solid colour using a single dye bath. $\implies$ Correct.
• In blend dyeing (e.g., polyester/cotton or wool/acrylic blends), union dyeing produces a uniform solid shade throughout the fabric from a single dye bath containing compatible dye classes.
• Reason (R): Dyes having affinity for different fibre types can be used to produce one solid colour. $\implies$ Correct.
• By formulating a combination of disperse dyes (for polyester) and reactive dyes (for cellulose) tailored to each fiber component's specific chemical affinity, both components absorb their respective chromophores at equal visual depths, yielding a solid uniform color.
• Conclusion: Both (A) and (R) are correct and (R) is the correct explanation of (A) (Option 1).

Correct option: (1) Both (A) and (R) are correct and (R) is the correct explanation of (A).