Given below are two statements, one is labelled as Assertion (A) and other one labelled as Reason (R).
Assertion (A) : The sex of a human offspring is determined by the presence or absence of a Y chromosome in the sperm.
Reason (R) : Sperm cells from males contain either an X or a Y chromosome, while egg cells from females contain only an X chromosome.
In light of the above statements, choose the most appropriate answer from the options given below.