I will be am mad....! Help me.

Today, I did my reading practice. After working for a little while, I became mad because And then I will be mad..Because I cannot understand certain topics completely!
What is their meaning!?!!!!!
For example,
"Which one of the following, if true, most helps to resolve the apparent discrepancy in the information above?"

"Which one of the following, if true, most calls into question the officials' argument?"

"Which one of the following, if true, most seriously calls into question the accountant's argument?"

"Which one of the following is an assumption on which the argument depends?"

And there are some other options that I don't understand, too.
For example,

"The owls, whose nesting sites are currently being destroyed by the gray squirrels, feed primarily on rodents."

"If you look at individual restaurants, however, you may find that the number of meals sold actually decreased substantially at every one of our restaurants that were in operation both last year and the year before."

Who can help me translate them.....?

Please...!~

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There were a few minor spelling mistakes such as "true." Remember to include a space after commas and periods.