Answer B
It is a black box testing approach
Divides the input domain into classes of data
1.If an input condition specifies a range, define one valid and two invalid equivalence classes
2.If an input condition requires a specific value, define one valid and two invalid equivalence classes.
3.If an input condition specifies a member of a set, define one valid and one invalid equivalence class.
If an input condition is Boolean, define one valid and one invalid class.