Designing shoes is hard work. It will pay off in the end. Identify the sentence that correctly combines the above passage into a compound sentence.

The two sentences are in opposition to each other, so you could say for example:

Designing shoes is hard work, but it will pay off in the end. (with or without the coma).

or:

Designing shoes is hard work; however, it will pay off in the end. (make sure to use this interpunction)