In the sum of products function $f(X,Y,Z)=\sum(2,3,4,5)$, the prime implicants are
1. $\overline{X}Y,X\overline{Y}$
2. $\overline{X}Y,X\overline{Y}\overline{Z},X\overline{Y}Z$
3. $\overline{X}Y\overline{Z},\overline{X}YZ,X\overline{Y}$
4. $\overline{X}Y\overline{Z},\overline{X}YZ,X\overline{Y}\overline{Z},X\overline{Y}Z$