Hydrogen bonding requires electronegative atoms like N or O with hydrogen.

Steps:

• Identify molecules capable of hydrogen bonding: those with H bonded to N, O, or F.
• During transpiration, water moves via cohesion (H-bonds between water molecules) and adhesion (H-bonds with polar plant surfaces).
• Evaluate each option: 1 (NH₃, has N-H), 2 (CH₄, no electronegative atom with H), 3 (CH₃CH₂OH, has O-H).
• Select pair that forms H-bonds with water: NH₃ and CH₃CH₂OH.

Why C is correct:

• NH₃ and CH₃CH₂OH both donate/accept H-bonds with water's O-H, aiding transpiration's capillary action per adhesion principle.

Why the others are wrong:

• A includes 2 (CH₄), which lacks polarity for H-bonding.
• B excludes 3 (CH₃CH₂OH), missing a key H-bond former.
• D excludes 1 (NH₃), omitting another valid H-bond donor.

Final answer: C