I advised her _ drink it.

Explanation

B is correct because it makes sense...When you want your writing to sound more formal and the sentence sounds better, you should use not to. Using not to protects the infinitive form of the verb. Many grammarians are resolute that infinitives shouldn't be split. They argue that the infinitive form is the true form of the verb and to add anything between "to" and the verb is wrong. There are some examples where this is correct. If we take the example, "not to be rude, but it's your fault," the word "not" is used before the infinitive "to be." In this sentence, not to cannot be replaced with to not as it changes the meaning and the sentence no longer makes any sense.