Citing the growing national debt, many economists have expressed

Can expert please explain what is the difference in using 'that' and not using 'that' in this question?

Just a friendly reminder to please please ALWAYS include your source when posting a new question! I have no idea where this question comes from, and it looks pretty suspect.

There's a decent answer to the question about "that" here, though! Consider the following:

• Mike has a debilitating fear of clowns. --> "fear of" is (correctly) followed by a noun
• Mike has a debilitating fear that a clown will steal his surfboard. --> "fear that" is (correctly) followed by a clause

The word "that" has a bunch of different uses in English (as described in detail here), and in this case, "that" is used to subordinate a clause. There's nothing inherently wrong with saying "fear of _____", but "fear of" needs to be followed by a noun only, and not an entire clause (i.e., a phrase with a subject and a verb). In this sentence, the fear is that "rising expenditures and use of aid packages will cause a downturn..." -- and that's an entire clause. So we need to use "fear that", and not "fear of" in this case.

But again, don't lose any sleep over this question, since it's likely not official, and we don't know where, exactly, it came from.

I hope this helps!

Hello Sir,

Can you please shed some light on the option "B" and "c". How "C" is wrong and B is correct. Although i got this question correct, i want to know the exact reason for elimination option "C".
Also, please tell how in option "B" have parallelism in that part but not in option "C".