Question

Glazing pottery can be tricky. The stunning results make the effort worthwhile. What should be included to best combine the sentences? ; , and , but when

Answer 1

Glazing pottery can be tricky but, the stunning results make the effort worthwhile.

Answer 2

The answer is B: But

 The conjunction But has the purpose of introducing an additional information that is different from what was said before, which is a contrasting idea. In the first sentence, the word tricky means a difficult activity, and the second affirms that despite the difficulty, it is worthwhile. Two contrasting ideas united by the conjunction but.