The resultant of three vectors 1, 2 and 3 units whose directions are those of the sides of an eauila

The resultant of three vectors 1, 2 and 3 units whose directions are those of the sides of an eauilateral triangle taken in an order is at an angle of

A

30∘ with the first vector

B

15∘ with the first vector

C

100∘ with the first vector

D

150∘ with the first vector