In nuclear reactors, 'moderators' are substances.
A. That slows down neutron
B. That limits the chain reaction
C. That helps to sustain the chain reaction
D. Without which chain reaction in most nuclear reactors would stop
E. Such as heavy water or D2O
Choose the correct answer from the options given below:
1
A, B, C and D only
2
A, C, D and E only
3
B, C and D only
4
A, B and E only