146. A patient accusing a doctor of malpractice will find it difficult to prove damage if there is a lack of some other doctor to testify about proper medical procedures.
(A) if there is a lack of some other doctor to testify
(B) unless there will be another doctor to testify
(C) without another doctor's testimony
(D) should there be no testimony from some other doctor
(E) lacking another doctor to testify
Only C, the best choice, manages to convey the meaning of the sentence efficiently and idiomatically. Choices A and D are plagued by awkwardness and wordiness. Choice A also introduces the unidiomatic phrase lack of some other doctor.
Choice B incorrectly uses a future-tense verb (will be) in the if clause; the if clause must use the present tense if it is preceded, as here, by a result clause that uses a future-tense verb (e.g., will find). Choice E introduces a dangling modifier: the lacking ... phrase cannot logically modify damage, the nearest noun.
What is the "if clause" in choice B? | 
