The Cygnus spacecraft was grounded last week ahead of its launch

In addition to what Daagh has mentioned

Because is always followed by Clause/ Because of followed by noun.

Inteneded meaning best conveyed by E

OFFICIAL EXPLANATION:

Creating a filter: We read the prompt. Supposing that we try the universal checks of subject and verb, and intended meaning, and we don't find an error, we can proceed to the answer choices and evaluate them exhaustively, skipping answer choice (A) initially.

Finding objective defects: In (B), "thereby raising" sounds funny and distorts the meaning of the sentence. It makes it sound like the spacecraft raised the levels. So (B) is out.

In choice (C), the construction at the beginning sounds weird. We look for a more objective problem and find it: it says "systems would malfunction," which is not parallel with the following "might be compromised." The intended meaning is that if one happens, the other will happen. Therefore, (C) is out.

Choice (D), similarly to (C), is not parallel due to the verb "to malfunction." So it's out.

That leaves us with (E), which sounds pretty good, and (A). We try to find a more objective difference and find it in the pronouns, "their avionics systems" and "its avionics systems." The avionics systems belong to the spacecraft, which is grammatically singular, so answer choice (A) is flawed.

The correct answer is (E).