• (A) Pusa Sona and (D) Sadbhavana: Dwarf, compact, naturally bushy, profusely branching small-flowered cultivars developed by ICAR-IARI and NBRI specifically for pot culture (pot mums).
• (B) Tata Century and (C) Snow Ball: Renowned standard, large-flowered, incurved cultivars grown as single-stem cut blooms or exhibition entries, NOT compact pot mums.

• Assertion (A) is correct: Chrysanthemums are exceptionally sensitive to water stagnation; excessive moisture causes severe wilt and dieback, necessitating porous media and unblocked drainage holes.
• Reason (R) is correct and explains (A): Waterlogged media displaces soil pore air, inducing acute root hypoxia/anoxia. Without oxygen, aerobic ATP generation ceases, roots cannot maintain nutrient uptake, ethanol/lactic acid fermentation accumulates, and opportunistic fungi (Pythium, Rhizoctonia) infect decayed roots, causing foliar chlorosis and complete plant mortality.

• Orchids are commercially classified based on minimum night temperatures required for optimal growth and flowering:

  1. Warm Orchids ($18\text{--}24^\circ\text{C}$ night, $25\text{--}32^\circ\text{C}$ day): Tropical lowland epiphytes including Phalaenopsis (Moth orchid) and tropical Dendrobium (Phalaenanthe section).
  2. Cool Orchids ($10\text{--}13^\circ\text{C}$ night, $15\text{--}20^\circ\text{C}$ day): High-altitude subtropical montane epiphytes and terrestrials including Cymbidium, Miltonia (Pansy orchid), and Odontoglossum.

• is incorrect because solid matrix priming hydrates seeds using moist solid carriers like vermiculite or peat moss.
• is incorrect because hydropriming involves soaking seeds in pure aerated water.
• is incorrect because halopriming involves soaking seeds in dilute inorganic salt solutions (e.g., NaCl, KNO3).
• is correct because biopriming is an advanced seed treatment combining physiological seed hydration with biological inoculation of beneficial antagonist microorganisms (such as Trichoderma spp. or Pseudomonas fluorescens) to control seed-borne pathogens and enhance seedling vigor.