Identify the modulation schemes for the shown signal constellation diagrams

A

(a)-QPSK (b)-BPSK (c)-QAM

B

(a)-QPSK (b)-OQPSK (c)-MSK

C

(a)-OQPSK (b)-QAM (c)-QPSK

D

(a)-OQPSK (b)-QPSK (c)-MSK