Correct Answer: E
Explanation:
- Three engineers from I, J, K and L must be chosen. The only combination are I J K - I K L - I J L - J K L - I J K L.
- Since I refuses to work with L, combinations I K L, I J L, and I J K L are ruled out. Thus the only combination with the engineer are I J K or J K L
- Since J refuses to work with M, and N refuses to work with O, the engineers I J K could only work with N and P or O and P.
- Thus possible combinations of the five-member groups are I J K N P or I J K O P
- Since J refuses to work with M, and L refuses to work with N, the engineers J K L could only work with O and P. Thus a possible combination of the group is J K L O P
- The only possible combinations are therefore
- I J K N P - I J K O P - J K L O P
It can be seen from the three combinations: I J K N P, I J K O P and J K L O P
That if O is rejected, the group must be I J K N P. Thus L is not in the group