prep1-88

88.     (29339-!-item-!-188;#058&003906)

A recent study has found amoxicillin, long a standard treatment for ear infections, as being about as effective as newer, more expensive antibiotics and causing fewer side effects.

(A) amoxicillin, long a standard treatment for ear infections, as being about as effective as newer, more expensive antibiotics and causing

(B) amoxicillin, long a standard treatment for ear infections, to be about as effective compared to newer, more expensive antibiotics and with

(C) amoxicillin, long a standard treatment for ear infections, to be about as effective as newer, more expensive antibiotics and that it causes

(D) that amoxicillin, long a standard treatment for ear infections, is about as effective as newer, more expensive antibiotics and causes

I can correctly choose D. But can anyone help explain the meaning and use of "long a standard treatment for ear infections"?

Thank you.