Which word or abbreviation in the sentence, if any, should be followed by a comma?

mr. alex jackson, ceo founded the company 10 years ago.

a.
ceo

b.
mr.

c.
there is no error in comma usage.

d.
founded

In this unit ,we learned about arguments and rhetoric. in an argument we ,not informal language.

The adventures of tom sawyer, chapter 1 (excert)what does tom do to prevent aunt polly from finding out that he ate her jam? a) tom hides under the bed and then in the closet b) tom hide under the bed and tries to blame the cat c) tom hides in the closet so that aunt polly would not see him d) tom tried to wash the jam off and lied to aunt polly about the cat

How did rick respond to this conflict