Question

Decide whether the underlined word below is a preposition, interjection or conjunction.

The last customer left, so we closed the shop.

Answer 1

which word is underlined. I will leave answer in comments.

Answer 2

The last customer left, so (conjunction) we closed the shop.

Step-by-step explanation:

A conjunction is a part of speech whose role is to merge two words/phrases/clauses/sentences. We may also call them linking words. There are three types of them: coordinating, subordinating, and correlative. Coordinating conjunctions link words, phrases, and clauses that are even in a grammatical sense. For instance: I like to eat apples and pears. Some of the coordinating conjunctions, like the one used in the given sentence, are: so, or, and, but, etc.