The example that contains an error in logic as worded is:
D. Mark's usual reason for not turning in his homework was because he forgot his backpack.
Here, we have an adverb of reason (because), which functions as a subordinating conjunction and makes up an adverbial clause of reason. Using the word "because" after previously using the word "reason", implicates some sort of redundancy.
The logical structure to express this idea would be the following:
D. Mark's usual reason for not turning in his homework was that he forgot his backpack.