Passage
…off, the rehabilitator selects a number seven feather from a collection kept exclusively for imping. If necessary, a number six or eight feather can be carefully trimmed with small scissors to the shape of a number seven feather.
The quill of this replacement feather is trimmed so that when the replacement feather is eventually attached to the quill stub still in the bird’s body, the repaired feather will( be equal in length) to the original, whole feather.
Question-
70
F. NO CHANGE
G. be equally long
H. equal the length
J. equal in length
Why is it F and not J?
Is there a particular grammar rule that dictates this choice?
Thankyou!