Genetically engineered male sterile crop plants may be produced by inserting

The correct option is C Barnase gene
The genetically engineered techniques have a pivotal role in developing male sterility and restorer systems. Chimaeric ribonuclease gene (barnase gene) expression within the anther selectively destroys the tapetal cell layer that surrounds the pollen sac, prevents pollen formation and leads to male sterility.

So the correct answer is option B.