Larva migrans manifestations caused by parasitic nematodes:

• Gnathostoma spinigerum (Spirurida nematode of felines and canines): In paratenic and aberrant human hosts, the advanced third-stage larva ($L_3$) cannot mature into an adult worm and undergoes erratic, aggressive migration. It causes Cutaneous Larva Migrans (migratory, pruritic subcutaneous nodules or creeping eruptions) as well as Visceral Larva Migrans (invading internal visceral organs, lungs, gastrointestinal tract, eyes, and central nervous system / eosinophilic meningoencephalitis).
• Toxocara canis: The classic agent of Visceral Larva Migrans and Ocular Larva Migrans.
• Ancylostoma caninum and A. braziliense: Classic causative agents of Cutaneous Larva Migrans (creeping eruption).
• Strongyloides stercoralis: Causes larva currens, a rapidly advancing serpiginous cutaneous track.
  
  Option analysis:
• Causes Visceral Larva Migrans (VLM) and Ocular Larva Migrans (OLM).
• Causes Cutaneous Larva Migrans (CLM).
• Causes larva currens.
• (Gnathostoma spinigerum): Correct. Causes both cutaneous swelling/nodules (CLM) and invasive organ involvement (VLM).

Clinical pathology of cutaneous habronemiasis (Summer Sores / Bursati) in horses:

• Statement (I) is true: Cutaneous habronemiasis is caused by third-stage larvae of equine stomach spirurid worms (Habronema muscae, Habronema microstoma, and Draschia megastoma). Larvae are deposited by intermediate vector flies (Musca domestica, Stomoxys calcitrans) into pre-existing cutaneous abrasions, wounds, or moist mucocutaneous junctions while feeding.
• Statement (II) is true: The trapped larvae provoke intense, non-healing, pruritic granulomatous reactions with caseous calcified granules on exposed parts such as the legs, withers, medial canthus of the eye, and prepuce/sheath. During winter, adult fly activity ceases, larval deposition stops, and lesions frequently regress and heal spontaneously, only to recur in subsequent warm summer seasons.

Specific gravities of standard diagnostic fecal flotation solutions in veterinary parasitology:

• Zinc sulphate solution (B): In standard clinical veterinary parasitology, zinc sulphate flotation solution is commonly prepared at a specific gravity of approximately $1.18$ ($33\%\ \text{w/v}$, Faust technique) to prevent distortion of protozoan cysts like Giardia.
• Saturated Sodium Chloride solution (A): Saturated $\text{NaCl}$ solution has a specific gravity of approximately $1.20$.
• $35\%$ Magnesium sulphate solution (D): Has a specific gravity of approximately $1.28$.
• Sheather's sugar solution (C): Concentrated sucrose solution prepared with phenol has a specific gravity of $1.27\text{--}1.30$ (typically adjusted to $1.30$).
  Arranging in increasing order of specific gravity yields:
  Zinc sulphate ($1.18$) $\lt $ Saturated $\text{NaCl}$ ($1.20$) $\lt $ $35\%\ \text{MgSO}_4$ ($1.28$) $\lt $ Sheather's sugar ($1.30$), corresponding to (B), (A), (D), (C).
  
  Option analysis:
• Incorrect ranking.
• Incorrect ranking.
• ((B), (A), (D), (C)): Correct. Accurately orders solutions from lowest to highest specific gravity.
• Reversed order.