... in the above problems. PT73.4.19 is a necessary ... -> B.
However in PT73.4.19, the correct answer ... good economic sense," whereas in PT73.4.19 JY does not ...
I do not understand the difference between answer choice C and D. How do you suggest that I decipher between two choices that are so close. I tried to incorporate them into the passage and incorrectly thought that D was a winner.