Correct Option: C  [ the father ]
Remark:
Explanation: The sex of a newborn baby is determined by the chromosome inherited from the father. Humans have 23 pairs of chromosomes — 22 pairs of autosomes and one pair of sex chromosomes. Females have two X chromosomes (XX), while males have one X and one Y chromosome (XY). The mother always contributes an X chromosome, but the father can contribute either an X or a Y. If the sperm carrying an X chromosome fertilizes the ovum, the child will be a girl (XX); if the sperm carries a Y chromosome, the child will be a boy (XY).