TC connotation Issue

Incase I don’t know the meaning of word “Startling “ how would I still able make semantic guess neutral or -ve. I found it neutral so I eliminated all the +ve and -ve options like (A,C,D) But it’s answer is A

The startling finding that variations in the rate of the Earth’s rotation depend to an ---- degree on the weather has necessitated a complete—-- of
the world’s time-keeping methods.

(A) unexpected. overhaul
(B) anticipated. recalibration
(C) indeterminate. rejection
(D) unobservable. review
(E) estimated. acceptance

Which blank are you talking about?

I find both blanks neutral

Okay so we should use semantics then. What does “startling” mean and which of the answer choices best supports that?

That was the problem. I didn’t know the meaning of word “Startling”.

Yeah, then you can’t really solve this one, so you’d guess and skip