Because the collagen fibers in skin line up in the direction of tension, surgical cuts made along these so-called Langer’s lines sever fewer fibers and is less likely to leave an unsightly scar.
for countable nouns (fibers) we have to use "few" rather than "less", so ignore option C & D. Now in non underlined portion it is mentioned that "
is less likely to leave an unsightly scar" so we have to use "a cut" rather than "cuts"
(A) Because the collagen fibers in skin line up in the direction of tension,
surgical cuts made along these so-called Langer’s lines
sever fewer
(B) Because the collagen fibers in skin line up in the direction of tension, a surgical cut
having been made along these so-called Langer’s lines severs
less(C) Because the collagen fibers in skin line up in the direction of tension, a surgical cut made along these so-called Langer’s lines severs fewer
CORRECT(D) With the collagen fibers in skin lining up in the direction of tension,
surgical cuts made along these so-called Langer’s lines
sever less(E)
With the collagen fibers in skin lining up in the direction of tension, a surgical cut made along these so-called Langer’s lines
sever fewer
ALL THE VERY BEST