For a MOD-12 counter, the FF has a tpd = 60 ns The NAND gate has a tpd of 25 n sec. The clock frequency is
Answer: A
For a proper working, the clock period should be equal to or greater than
tpd = Mod 12 - 4FFs = 4 x 60 = 240 nsec.
Total tpd = 240 + 25 = 265 nsec.