The sentence requires two correct words to fill the blanks. Let's analyze the options:
- The first blank is asking for the number of hours of tennis played. Since "two" fits the context (a quantity of hours), (D) is the correct choice.
- The second blank refers to the level of tiredness after playing tennis. The correct phrase here is "too tired," meaning very tired, which is the appropriate expression in this context. Thus, (D) is correct.
Hence, the correct answer is (D) two / too.