which one is correct:

Question

1. the box contains two slides labeled "A" or "B"
2. the box contains two slides labeled "A" and "B"

Answer 1

# 2 is correct.

However, both sentences need capitals at the beginnings and periods at the ends.

Answer 2

Ms. Sue, is there a rule for this that I can use to justify your answer. I have a hard time convincing a colleague that you are correct.

Answer 3

When you use "or" it means that the two nouns are singular. You have two slides, so they are labeled A and B. This implies that one slide is A and the other slide is B.