Answer:
(B)

Explanation:
Given: From the figure, it is given that in triangle DEF, DE=13 and DF=7
To find: The value of EF.
Solution: It is given that From the figure, it is given that in triangle DEF, DE=13 and DF=7, therefore using Pythagoras theorem, we have

Substituting the given values, we get





Thus, the value of EF is
.
Hence, option B is correct.