Read this excerpt from a story.

Weeks ago, students had been assigned the task of building a car from scratch. Mr. Daniels had given a list of suggested materials, but the project had very few rules. The car only had to propel itself for 6 inches. Still, the project had stumped Troy. The cars he had attempted would barely roll, let alone propel themselves. Finally, at 9:15 last night, he had asked his dad for help.

Troy's dad had willingly brainstormed with him, gathered materials, and created a workspace. Unfortunately, Troy had fallen asleep in the process. When he woke up this morning, his dad had built an impressive car and placed it in a shoebox.

Troy peered into the box at his dad's creation. He knew it would roll with ease. He might even win some sort of prize. He looked around the classroom. Other students were sneaking peeks at their cars, hidden in bags and boxes. Many were grinning in anticipation. Troy felt his stomach lurch.

When Mr. Daniels announced that it was time to reveal the cars, Troy raised his hand.

"Mine is not ready today, Mr. Daniels. I'd like to turn it in late if you'll let me."

Which explains why Troy tells his teacher that his car is not ready?

He is worried about the car's ability to move.
He feels nervous about giving presentations.
He is concerned about keeping his car a secret.
He feels guilty about his dad's efforts to help him.