Take another look at the sentence:
Because Henry enjoyed impressing his girlfriend Gloria, he __________ for the expensive dinner with his brand new credit card; he would worry about the shocking statement when it arrived in the mail next month.
The sentence requires the simple past of pay, an irregular verb. Paid is the simple past form.
|Verb||Simple Present||Simple Past||Past Participle|
Payed, the form you chose, is a spelling error. Before you continue, review the rules for irregular verbs.