Which is correct?

Correct answer: I saw a movie.

Explanation: Choose the article based on the initial sound of the following word, not strictly the first letter.

• Use 'a' before words that begin with a consonant sound (for example: a cat, a movie).

• Use 'an' before words that begin with a vowel sound (for example: an apple, an hour).

• Because 'movie' begins with the consonant sound /m/, the correct article is 'a', so the correct sentence is 'I saw a movie.'

• Other errors in the choices: using two articles in a row ('the a movie'), using 'an' before a consonant sound ('an movie'), and omitting a required article ('I saw movie').