Which of the following is a complex sentence?

By Anthony
1 Min Read

Which of the following is a complex sentence?

I really need to go to work, but I am too sick to drive.
Should we start class now, or wait for everyone to get here?
Because I was running late for work, I was snippy with him.
I have been on rather too many planes and trains recently.

Option 3 : Because I was running late for work, I was snippy with him.