Sentence Correction

It was anomalies in the orbit of Uranus that led to the discovery of Neptune.

A) It was anomalies in the orbit of Uranus that
E) The anomalies in the orbit of Uranus was what

My pick was E), because it looks more concise to me. However, the correct answer is A). The explanation is that the subject and verb don't agree in E). Doesn't the same error apply to A) given the explanation on E)?

Thanks in advance!

Shouldn't A) written as Those were anomalies in the orbit of Uranus that led to the discovery of Neptune.
I think that the phrase "anomalies in the orbit of Uranus" is plural.

I am so confused!

I very well remember coming across this question during my prep.

Please note that the author is talking about the reason for discovery and not the reasons.
Hence "It was anomalies" is correct.

Ask yourself, "What led to the discovery?"
Answer is "It was" that is "Reason for that to happen was "existence of anomalies"

Hope you got this.

Thank you so much! That helps a lot. GMAT is a tricky business.

here the discovery of anomalies that led to....
It was the anomalies means....it was the discovery of anomalies...here is discovery is the subject and so verb WAS is correct...In E the anomalies is taken as the reason...and also here the subject is THE ANOMALIES and so WERE shld be the verb....

pahwa...good explanation

Great explanations! Thanks again!