Which sentence does not contain any errors in the use of italics or quotation marks?
a. is the word "their" or the word "there" correct in that sentence?
b. the word love appears five times in that note.
c. i often forget to cross my t's when i'm writing quickly.
d. mike's home address begins with a "2."

I don't see any italics in the question, but:

In A, there should be commas after each item. In the U.S. the commas would be inside the quotes: Is the word "their," or the word "there," correct in that sentence? I've read that in some other areas the convention is to put the commas outside the quotes: Is the word "their", or the word "there", correct in that sentence? but I'm not familiar with that.

In B, the word "love" should be quoted as it appears in this sentence.

In C, I think (I'm skilled, but not an certified grammarian) the "T" should be quoted, like so: I often forget to cross my "T"s when I'm writing quickly.

D is, I believe, correct. Again, this is by U.S. conventions. Elsewhere (England, at least) I think it would be written as: Mike's home address begins with a "2".