“He had to go . . . . . . . . square one.” A. back to B. under C. onto (on to) D. over

The correct answer is A. back to.

The phrase “go back to square one” means to start again from the beginning. It is often used when someone has made a mistake or failed at something, and they need to start over.

The other options do not make sense in the context of the phrase. Option B, “under,” would mean to go below the starting point. Option C, “onto,” would mean to move to a new starting point. Option D, “over,” would mean to go past the starting point.

Here are some examples of how the phrase “go back to square one” might be used in a sentence:

• “I’m so frustrated! I’ve been working on this project for hours, and I’m back to square one.”
• “I know I made a mistake, but I’m willing to go back to square one and start over.”
• “I’m not sure what I did wrong, but I need to go back to square one and figure it out.”