Which method has led to the development of several high yielding varieties of millets which are resistant to the water stress?

The correct option is A Hybrid breeding
Mutation breeding
Mutation breeding is a technique that induces mutations in the genetic material of the plant to create a desired character that is not usually found in the parental type.

Hybrid breeding
Hybrid breeding is a process where cross hybridisation is carried out between two organisms with desired qualities to obtain a mix of both the characteristics in the offspring. The development of varieties that are resistant to water stress are developed through hybrid breeding.

Biofortification
Biofortification is a process by which the nutritional quality of food crops are enhanced using conventional breeding methods. It has no application in producing plants resistant to water stress.

Conventional breeding
Conventional breeding is a technique which uses older plant breeding methods and natural processes for development of a new variety.