I'm confused with the info u have given. U ovulate 2 weeks after the 1st day of your period. If u started your period on the 4th, the 11th is too soon to be pregnant. Also, u can't get pregnant while on your period. If u are for sure pregnant, I would say guy #1 since u had sex with him 2 weeks before your period. U were ovulating on that date.
I would say guy #1 but u had a period a few days after sex with him. Guy #2 seems unlikely bc typically you can't get pregnant while on your period. Are you sure you are pregnant?
If the only time you slept with the first guy was February 26, and you are certain you got pregnant on March 11, what is the question exactly? If you are saying you didn't have sex on March 11, are you asking how long sperm can last in the female reproductive system? Longest I've ever seen estimated was 7 days. Was the period that began March 4 a normal period? If so, the guy you had sex with on February 26th would be pretty effectively eliminated, unless you had sex with him again at a later date. Periods don't come when you're pregnant. How did you get the date of March 11?