Wooden doors swell up and get stuck during rainy season due to

Answer: Option B

Wooden doors swell up and get stuck during the rainy season due to Imbibition.
Imbibition is a special type of diffusion that takes place when liquid is absorbed by solids-colloids causing an increase in volume.
Water surface potential movement takes place along a concentration gradient; some dry materials absorb water. A gradient between the absorbent and the liquid is essential for imbibition.
Dry wooden doors imbibe water from the moisture in the atmosphere during the rainy season and swell up.