What will be the most useful agent for him to achieve fertility?

A 16-year-old boy was referred to the endocrine clinic with symptoms of delayed puberty.

On examination, he had a reduced sense of smell, small-sized testes and underdeveloped secondary sexual characteristics.

Investigations:

serum testosterone3.5 nmol/L (9.0C35.0)

serum follicle-stimulating hormone1.0 U/L (1.0C7.0)

serum luteinising hormone1.5 U/L (1.0C10.0)

serum prolactin220 mU/L (<360)

MR scan of brainnormal

He asked about his future fertility.

What will be the most useful agent for him to achieve fertility?
A . bromocriptine
B . clomifene
C . gonadotropin-releasing hormones
D . octreotide
E . testosterone