The resultant of vec(A) and vec(B) is perpendicular to vec(A). What is angle between vec(A) and vec(B) ?

The resultant of vec(A) and vec(B) is perpendicular to vec(A). What is

1.	The resultant of vec(A) and vec(B) is perpendicular to vec(A). What is angle between vec(A) and vec(B) ?
Answer» `COS^(-1)((A)/(B))` `cos^(-1)(-(A)/(B))` `SIN^(-1)((A)/(B))` `sin^(-1)(-(A)/(B))` ANSWER :B