Answer: D. If Rebecca won the lottery, she could pay her tuition easily.
Explanation:
Conditional sentences are used when talking about hypothetical situations and their consequences.
A conditional sentence contains a conditional clause (if-clause) and the main clause (consequence).
There are four types of conditional sentences in the English language: zero, first, second and third conditional.
The sentence 'If Rebecca won the lottery, she could pay her tuition easily' is a conditional type 2. Second conditional sentences contain past simple tense in the if clause and auxiliary modal verb (could, would, should, might) in the main clause. We use second conditional for actions/events that are not likely to happen in future.
