Question

Select the clause from the drop-down menu to correctly complete the sentence.

Today, we used the boat ************** instead of the other boat.

A) that our grandfather built
B) , that our grandfather built
C) , that our grandfather built,
D) that our grandfather built,

**EDIT**
Answer is A "that our grandfather built"

Answer 1

ANSWER:

A ) that our grandfather built

Answer 2

Today, we used the boat A) that our grandfather built instead of the other boat.

The chosen sentence is an essential adjective clause, meaning that it acts as an adjective, that is to say, it describes or gives characteristics to the noun "boat", and it's essential since the reader needs the information of the clause to know what boat the speaker is referring to.

Option A is the correct answer because the grammar rule holds that essential clauses do not require commas. Unlike nonessential ones, who does require commas.