April's Colleague Nathan Has Consistently Pestered Her to Go Out

April's colleague Nathan has consistently pestered her to go out on a date with him. Though she has refused his offer several times, he keeps persisting. She found an envelope on her desk from Nathan with inappropriate pictures and cartoons, which left her infuriated. She now intends to go discuss the matter with the human resource department of her company. Which of the following forms of discrimination is April most likely to cite?

A) mobbing
B) sexual harassment
C) electronic harassment
D) exclusion
E) cyberstalking