Which of the following is an example of using nonverbal communication to complement verbal communication?
a. clapping after a performance, yelling/cheering during a sporting event
b. holding up a hand to indicate you do not wish to be interrupted or to stop communication
c. smiling while recounting an experience you found amusing
d. crossing fingers to indicate lying

The key part here is that the verbal communication should complement verbal communication - so there needs to be some verbal communication too. In options a) and b) there is no verbal communication involved - they are not correct.

In C the nonverbal communication doesn't really complement the verbal communication: it doesn't bring anything new into the conversation.

So the correct answer is d:  it brings something new into the conversation!

This would be a example of a "i want to be single person"