We need to check two things here — correct grammar and correct word usage.
Firstly, “it’s” is a contraction for “it is” or “it has” and is never used for possession. For possession, we use “its” without an apostrophe.
This means options (A) and (D) are automatically wrong because they use “it’s” incorrectly to indicate possession.
Secondly, we must decide between “increased” and “enhanced.”
“Increased” means to make something greater in amount, number, or degree — this makes sense with “advertising expense,” which refers to a monetary amount.
“Enhanced” means to improve in quality, value, or attractiveness — which is less appropriate here because an “expense” is not improved, it is increased or reduced.
This eliminates (C) because “enhanced” is not idiomatically correct for expense amounts.
Therefore, (B) is correct: it uses “its” for possession and “increased” to match the idea of spending more money.