“To persuade my audience that long-term exposure to electromagnetic fields can cause serious health problems” is a specific purpose statement for a persuasive speech on a question of（）。

“To persuade my audience that long-term exposure to electromagnetic fields can cause serious health problems” is a specific purpose statement for a persuasive speech on a question of（）。
A.value
B.fact
C.attitude
D.policy
正确答案：fact