An aggregate is said to be flaky if its least dimension is less than
(A) 1/5th of mean dimension
(B) 2/5th of mean dimension
(C) 3/5th of mean dimension
(D) 4/5th of mean dimension
(A) 1/5th of mean dimension
(B) 2/5th of mean dimension
(C) 3/5th of mean dimension
(D) 4/5th of mean dimension