Which is the right posture or technique to have a handshake？A．With one"s thumb up.B．Having

Which is the right posture or technique to have a handshake？

A．With one"s thumb up.

B．Having a loose grip.

C．With one"s palm down.

D．Having one"s hands pumped five times.

请帮忙给出正确答案和分析，谢谢！