I believe the answer is A. Have a blessed day.
The answer for this question is letter "B.Fission releases energy, and its products have greater stability."
Fission and Fusion are both nuclear reactions that when they release energy, they make the nuclei more stable. So among the choices, option B is the most fitting for the definition.
Answer : The significant digit is 6
Explanation :
Multiply
by 
Now, on multiplying


Now, the significant digit is 6.
Hence, this is the required solution.