Which sentence is a run-on sentence ?

Writing
Tutor: None Selected Time limit: 1 Day

My neighbors cat strolls our backyard everyday, but i'm not sure why.

Because his electricity bill perplexed him, Mr. Arnold scratched the top of his head. (i chose this one and quia marked it wrong.)

The city plans to build new tennis courts at the park many athletes will be happy.

May 19th, 2015

The city plans to build new tennis courts at the park many athletes will be happy.

This is a run-on sentence because there should be a period after the word park.

May 19th, 2015

Studypool's Notebank makes it easy to buy and sell old notes, study guides, reviews, etc.
Click to visit
The Notebank
...
May 19th, 2015
...
May 19th, 2015
Feb 22nd, 2017
check_circle
Mark as Final Answer
check_circle
Unmark as Final Answer
check_circle
Final Answer

Secure Information

Content will be erased after question is completed.

check_circle
Final Answer