Take a look at the sentence again:
Because her hands were still slippery from the dishwater, Marilyn dropped
the watermelon, which __________ on the floor in an explosion of pulp and
seeds.
The sentence requires the past tense of burst, an irregular verb which always has the same form. Burst, then, is the simple past form.
| Verb | Simple Present | Simple Past | Past Participle |
| burst | burst(s) | burst | burst |
Busted, the choice you made, is slang. Although people do use busted, you should avoid it, especially in formal situations. Before you continue, review the rules for irregular verbs.
Go back to the sentence to try again.