Giant mouse has been produced through
A. Tissue culture
B. Gene differentiation
C. Gene manipulation
D. All of the above

Hint:Mice are a useful model for genetic experimentation and study, since their tissues and organs are identical to human tissues and bear almost all genes present in humans.

Complete answer:
Animals that possess manipulated DNA to contain and express an additional gene are called transgenic animals. Transgenic organisms are also produced for commercial purposes. Many transgenic animals such as rats, fish, sheep, cows, rabbits, and pigs have been developed, but more than 95% of all current transgenic animals are mice.

Mice can be engineered by injecting a targeting vector carrying the desired gene into a zygote or embryonic stem cells which are then inserted into a blastocyst. There are many types of genetically modified mice: transgenic mice, knock-out mice and mice with modified or inducible gene expression. Although the transgenic mice with the new gene structure have been randomly introduced into the genome, the knockout mice have a gene structure implanted at a particular site. Thus, mice may be injected with genes that encourage muscle size and growth, resulting in genetically engineered mice that can be twice as large as normal mice.

Thus, the correct answer is option C i.e., Gene manipulation.

Note:Transgenic animals are produced for a variety of reasons. Some of the common reasons include the study of the physiology and development of the body, study of disease, testing of vaccine and chemical safety, and for obtaining biological products.