"It's fine with me if you don't want to come to the party."
Explanation:
Out of the four options listed, the one that is written in standard English would be "It's fine with me if you don't want to come to the party." The other options are mostly written correctly but have one or two words that make the sentence into urban slang. For example, "fam" is urban slang for family while tho is a shortened way of spelling though. The sentence "Michael would of given you a pen if you had asked." is wrong because instead of the word "of" it should have been "have"
