Many financial analysts consider an upward trend in a firm’s current ratio <<a sign of improving liquidity.>>

A- a sign of
B- as a sign of
C- to be a sign of
D- a sign of their
E- as being a sign of

I chose C but the explanation says: This answer choice uses the unidiomatic and redundant construction “to consider X to be Y.”
Correct answer is A
The original sentence uses the correct idiom “to consider X Y” and draws a logical and structurally parallel comparison between two nouns: “a trend” and “a sign.”

This make sense, my question is consider never goes with "to"? consider to is always wrong?

Thanks

On the GMAT, unlike in the "real world," consider stands alone. Consider to, consider to be, consider as - actually consider (anything) - are incorrect!

-dan