The correct answer is C.
In a periodic sentence the main clause is at the end. This is used for emphasis, by putting reasons for something at the beginning before the final point is made.
In his speech, Gehrig uses many periodic sentences to highlight how lucky he has been troughout his life.
An example of this rhetorical element is: "When you have a wonderful mother-in-law who takes sides with you in squabbles with her own daughter -- that’s something."
An anaphora refers to the repetition of a word or phrase in successive clauses or phrases.
Gehrig repeats the phrase "Sure I'm lucky" to put extra emphasis in the fact that, even though he got a bad break, he has had a great deal of luck during his life.
