(A) is the right answer.
A Sertoli cell (a kind of sustentacular cell) is a 'nurse' cell of the testes that is part of a seminiferous tubule. It is activated by follicle-stimulating hormone and has FSH-receptor on its membranes. It is specifically located in the convoluted seminiferous tubules (since this is the only place in the testes where the spermatozoa are produced). Development of Sertoli cells is directed by the testis-determining factor protein.