The correct word to fill in the blank is 4. advice. The phrase should be, "I need some advice," because "advice" is an uncountable noun that means a recommendation or guidance. 

Advice (noun): A suggestion or recommendation about what you think someone should do.

• Example: "I need some advice on my career."

Advise (verb): To give counsel or to recommend.

• Example: "I would advise you to study for the test."

Advised (verb, past tense): Gave counsel or recommendation.

• Example: "He was advised to seek professional help."

Advises (verb, third-person singular present): Gives counsel or recommendation.

• Example: "She advises clients on their financial planning."