Which sentence does not contain any errors in comma usage?

a.
mrs. fanelli whom we know from our neighborhood can fly airplanes.

b.
a famous author, whose name escapes me right now will give a speech at the library.

c.
bobby thompson, whose middle name is herbert, lives three doors away from us.

d.
vanessa whom you don't know, will ride on a float in the parade.

The sentence that does not contain any errors in comma usage is option C. Bobby Thompson, whose middle name is Herbert, lives three doors away from us. The rule of comma applied here is that, when an additional information is added within the sentence, it should be separated by a pair of commas. This information, in a form of a subordinate clause, is only used to add information about what is being talked about in the sentence.