Choose the correct option to fill in the blank.

Some of the people _____ to the party can't come.

who were invited

The correct answer is Option (3) → who were invited

This sentence requires a relative clause to describe the people. The people are the recipients of the invitation, meaning the action is done to them (passive voice).

• Who were invited is a relative clause in the Past Simple Passive voice that correctly identifies the people who received the invitation.