The hybrid seed production technique of bottle gourd is:

Correct option is B

In bottle gourd hybrid seed production, pinching of male flowers is done to prevent self-pollination and ensure cross-pollination for hybrid seed production.
(a) Pinching of female flowers: Reduces fruit set, not applicable here.
(c) Bagging: Prevents unwanted pollination but not a primary hybrid technique.
(d) Hand pollination: Used but secondary to pinching.
Important Point: Proper timing and technique ensure maximum hybrid seed yield.