Directions: Select the most appropriate filler(s) for the blank(s) such that the sentence makes coherent sense.

The ________ that sometimes strains the patient - doctor relationship when lawyers seek medical care is at an all time high.

The clause following “when” provides an explanation to the clause that precedes it. “Friction” (disagreement or conflict) is the only option that would be coherent with “strain” in the sentence. Hence, (3) is the answer.
'Abrasion' is a scraping or rubbing off, as of skin, therefore wouldn't convey cogent meaning to the sentence.