however fits correctly into the 'blank' in your text. whereas is a conjunction that requires a single sentence with two parts.. If you want to use it, you'll have to rewrite your two sentences as one.
New words, one handy idiom, and a 2-minute quiz — delivered to your inbox to keep your streak alive.
AnonymousI know that the right answer is however but why exactly?'whereas' has to be at the beginning of a clause; 'however' can begin or end the clause or interrupt it in various places.