Answer:
It is (supposed to be) a complex sentence, but you neglected to insert a very necessary comma after the word 'row.'
Explanation:
After eating pizza for nights in a row, Christian vowed never to order from Pete’s Pizza again.
A complex sentence is one that contains an independent clause and a dependent clause.
In the pizza sentence, the dependent clause is the first clause.
C is the best option here, as the other two alienate the reader.
B - too specific for the purpose
While that would be a good topic sentence, it is far too specific for the thesis of an entire essay
