Take a look at the sentence again:
On Christmas Eve, Captain Beane wore a pair of antlers while greeting passengers
boarding his 727. The costume __________ little trust in Louise, whose fear
of flying required a serious pilot.
The sentence requires the past tense of build, an irregular verb. Built is the simple past form.
| Verb | Simple Present | Simple Past | Past Participle |
| build | build(s) | built | built |
Build, the form you chose, is present tense, which does not fit the timeframe of the sentence. Before you continue, review the rules for irregular verbs.
Go back to the sentence to try again.