She had to put product in her hair to tame frizziness
The answer in the blank is common themes. It is because using common themes or including them on the speaker's speech could make the audience relate on the topic and to be intrigued or to be interested. With this method, not only will the speaker give out his information but he or she could capture the attention of the audience.
I think D though i could be wrong sorry if that's the case...
