Answer:(c)
Explanation:
option c represent 

According to the law of vector addition, When two vectors are added such that they are represented as two sides of a triangle in magnitude taken in the same order, then the third side represents the results of the two with order opposite of two.
In option c order of 
 and
 and 
 are same and thus third side represent the resultant of two.
 are same and thus third side represent the resultant of two.