The following sentence has been divided into four segments. Identify the segment that contains a grammatical error.

Don’t go / outside / because it is / raining heavy.

The correct answer/option containing the grammatical error is: raining heavy.

Explanation:

In English grammar, verbs are modified by adverbs, not adjectives.

In the given sentence segment "raining heavy", the word "raining" is a verb (in the continuous form). The word "heavy" is an adjective, which is used to describe nouns or pronouns.

To correctly modify the verb "raining", we must use the adverb form heavily instead of the adjective "heavy".

Corrected Sentence:
Don’t go outside because it is raining heavily.

Therefore, the segment "raining heavy." contains the grammatical error.