Ans.
Dolly was first cloned mammal, from a somatic cell of adult sheep, using the nuclear transfer process. She was produced using a technique that involved formation of a hybrid cell by transferring the nucleus of a somatic cell (or adult cell) into a cytoplasmic donor (a cell, from which nucleus was removed).
The resulting hybrid cells was divided and developed into blastocyst, which was then implanted into a surrogate mother.
Thus, the correct answer is somatic cell.