Fill in the blanks with the appropriate past tense:

I did not have any money because I __________ my wallet at home. (Leave)
a. Had left
b. Has left
c. Left
d. Will leave

Hint: The action’s scope has been terminated in the past itself.

Complete step-by-step answer:

The Past Tense denotes those actions that have already taken place in the past. To frame verbs in the past tense, you must add the suffix ‘ed’ to the conjugated form of the infinitive of the verb. ‘Infinitive’ refers to the ‘to form’ of a verb. E.g. - to meet.
There are four types of past tenses:
The Simple Past Tense is used when the action is indefinite in the past. It doesn’t make use of any auxiliary verb.
The Past Continuous Tense is used when the action is continuous in the past. The infinitive form of such verbs is preceded by the auxiliary was.
The Past Perfect Tense is used when the action has been completed in the past itself. The infinitive form of such verbs is preceded by the auxiliary had.
The Past Perfect Continuous Tense is used when an action is continuous up until a point in the past. The infinitive form of such verbs is preceded by the auxiliary had been.
In the above question, the action has been terminated in the past itself. We know for a fact that the person left his wallet behind and the action was final. This means that the tense of the action is the Past Perfect Tense. Following the rules of conjugation, a correct answer is an option ‘a.’ had left.

 Note: To avoid making errors, consider when the action started and ended in the past.