Final answer:
The hormone testosterone is responsible for genital development, increased height, the deepening of the voice, and other secondary sexual characteristics in boys during puberty.
Step-by-step explanation:
The hormone testosterone is associated with various developmental changes in boys during puberty. It is produced by Leydig cells in the testes and is responsible for genital development, an increased height, and a deepening of the voice. During adolescence, testosterone levels rise, leading to secondary sexual characteristics such as the growth of facial, axillary, and pubic hair, increased muscle bulk, and the beginnings of the sex drive. The proper function and continued presence of this hormone are imperative for the male reproductive system.
So, the correct answer to the question is A) Testosterone.