The term string is used for
(A) The underside of a stair
(B) Outer projecting edge of a tread
(C) A sloping member which supports the steps in a stair
(D) A vertical member between two treads
(A) The underside of a stair
(B) Outer projecting edge of a tread
(C) A sloping member which supports the steps in a stair
(D) A vertical member between two treads