The president resigned; the whiff of scandal remained otherwise therefore immediately nevertheless

The correct answer is "nevertheless"

Explanation:

In the sentence, the only possible option is "nevertheless" since it is the only words that expresses contrast. According to the meaning of the sentences, contrast should be reveal between them. Another synonym for nevertheless is "however".

The adverb "therefore" is used to express cause and effect.

The adverb "immediately" expresses time.

The adverb "otherwise" means "or else"

you have to tell us what you're talking about or it's impossible to answer.