Explanation:

- The sentence describes an action that had already been completed before another event. In such cases, we often use the past perfect tense in one clause and the simple past in the other.

- Option 1: reach

- Incorrect, as it is in the present tense and does not fit the past context of the sentence.

- Option 2: reached

- Correct. The past simple "reached" complements the past perfect "had won," indicating that we arrived after she won.

- Option 3: had been reaching

- Incorrect. The past perfect continuous is not needed here, as there is no ongoing action implied.

- Option 4: are reaching

- Incorrect. This is in present continuous tense, which doesn't fit the past timeframe of the sentence.