AAMC biology question pack v1, question 49 does not make any sense

Question (no context from passage needed):

In Experiment 2, the increased blood pressure resulting from the higher-than-normal concentration of ADH most likely affected the urinary output of Substance A by increasing the:

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A

glomerular filtration rate.

B

Tm of solutes.

C

water reabsorption from the tubules.

D

concentrating ability of the loop of Henle.

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Answer is somehow A. But ADH only affects the collecting duct??? how does this work???