Please provide complete step-by-step explanation. Thanks!

You are 65- years old and considering retiring and drawing your Canadian Pension Plan (CPP) benefits. Assume you have contributed the maximum for a total of 40 years, since you started working at age 25. Now, you have been told that you can delay that start of your benefits by five years to the age of 70, in which case your benefits will increase by 42%. Assume that real (inflation-adjusted) interest rates are 2%, and that you are absolutely certain that you will only live to the age of 85. Which is the better option for you?