Synthesis phase in the cell cycle is called so for the synthesis of more of:
(a) RNA
(b) RNA and proteins
(c) DNA
(d) Glucose
Synthetic phase in the cell cycle is called so because during this period of cell cycle DNA replicates and the amount of nucleic acid is doubled. So, because of the synthesis of more of nucleic acid it is known as synthetic phase.
So, option (c) is correct.