Final answer:
Option b, where a teacher offers better grades in exchange for sexual favors is an example of quid pro quo sexual harassment, which is illegal and involves trading organizational rewards for sexual acts. The answer is option B.
Step-by-step explanation:
The scenario that best depicts quid pro quo sexual harassment is 'A teacher offers to help a student improve their grades in exchange for sexual favors'. Quid pro quo harassment refers to situations where organizational rewards, such as better grades, promotions, or salary increases are offered in exchange for sexual favors or where such rewards are withheld when sexual advances are refused. This form of harassment is illegal and violates organizational policies.