Answer: b)False
Explanation: The presence of Y chromosomes trigger the development of male characteristics and organs, but does not necessarily guarantee that they will develop fully. This is because environmental factors during pregnancy can also affect reproductive organ development. Thus, the Y chromosome doesn't guarantee the development of male sex organs. (In the field of biology, very few phenomenon are guaranteed, as there are always exceptions)
For example, mutations in other genes can disrupt hormone release, thus resulting in male sex organs not developing or being malformed. In additional, males with multiple copies of the X chromosome may also have underdeveloped male sex organs. To summarize, mutations in other genes or environmental factors can disrupt male sex organ development, even in the presence of the Y chromosome.
Thus, the Y chromosome doesn't guarantee development of male secondary sex organs.