What form of characterization is most often used in drama?

The correct answer is:

Indirect characterization

Indirect characterization is the process how the writer shows the personality of the characters indirectly, not indicating explicitly which actor represents the character, but through speech, actions and appearance. Drama plays usually don't have a narrator describing each character, so the audience has to gather the type of person the character is based on their behaviour.

showing or suffering from nervousness, fear, or a lack of confidence

the characters in string all have major secrets that they strive to avoid revealing throughout the play.