Which sentence does not contain any errors in comma usage?
a.
sam ate his breakfast, three pancakes, rather slowly.
b.
mr. gregory the store owner, smiles, all the time.
c.
barry the goalie, joined the team first.
d.
has someone heard kevin's new song a children's lullaby?

The sentence that does not contain any errors in comma usage is A. Sam ate his breakfast, three pancakes, rather slowly. In B, there should be a comma before the store owner, and after if, because that is an appositive phrase describing the subject. In C, the goalie should be separated from the rest of the sentence by two commas. In D, there should be a comma before a children's lullaby.