How many subsets of exactly two elements does a set of five elements have? A.10 B.26 C.7 D.32

Answer:Option: A is the correct answer.                 A. 10Step-by-step explanation:We know that the number of subsets of exactly ''r'' elements that is formed by the help of n elements is calculated by:             [tex]n_C_r[/tex]Since here we have to chose 2 elements out of the 5 elements in order to form a subset.Hence, we have:   n=5 and r=2Hence, the number of subsets are:[tex]5_C_2=\dfrac{5!}{2!\times (5-2)!}\\\\\\5_C_2=\dfrac{5!}{3!\times 2!}\\\\\\5_C_2=10[/tex]Hence, the number of subsets are:                                    10