Answer: Hence, Option 'B' is correct.
Explanation:
Methods of solving the systems of non linear equations:
- Isolate a variable in one of the equations.
 - Replace one variable in the non linear equation with an equivalent expression.
 - Adding the two equations together.
 - Substituting a value in place of one of the variables to solve the remaining variables.
 
So, the last step would be Option 'B'.
Hence, Option 'B' is correct.