Answer:
(D)15
Step-by-step explanation:
Given a set A, a proper subset of A is any subset of A that is not equal to A.
If a set has n elements, the total number of subsets of the set will be:
In the given set:
![\begin{gathered} L=\left\{ \operatorname{mm},cm,m,\operatorname{km}\right\} \\ n=4 \\ \text{Number of Subsets=}2^4=16 \end{gathered}]()
Therefore, the number of proper subsets of the given set will be:
