Let XXX be a discrete random variable such that P(X=k)=c⋅kP(X=k) = c \cdot kP(X=k)=c⋅k for k∈{1,2,3,4}k \in \{1, 2, 3, 4\}k∈{1,2,3,4}. Find the value of ccc.
1/101/101/10
1/41/41/4
1/51/51/5
1/61/61/6