Answer :
For the first sentence the right answer is variant A because ' lapping the cold milk ' it's the developed appositive.It can not be the variant D because the sentence needs just only one comma after Jeremy.
For the second sentence the right answer it is variant C because it no needs any comma. It can't be the variant D because it's missing a comma after cat.
For the second sentence the right answer it is variant C because it no needs any comma. It can't be the variant D because it's missing a comma after cat.
A. The kitten, lapping the cold milk, must be the hungriest.
The kitten must be the hungriest is a sentence by itself. Adding "lapping the cold milk" gives meaning to "hungriest", but is not needed. It is "extra information"
C. The boy hurt his left arm playing volleyball yesterday.
The two sentences with commas did not use them correctly, and so C is your best answer
hope this helps