Question PPF amount invested and Safe investment

Ok here is my question
A) if I invest Rs 1000 monthly basis on my PPF account so I would pay Rs 12000 (1000*12) in a year so after 15 years I will receive ₹ 3,51,891

B) if I invest Rs 12000 yearly basis on my PPF account, I will receive ₹ 3,51,891 after 15 year

so in both cases, I will Receive ₹ 3,51,891 after 15 years


instead of that, I should opt risk-free investment for 11 months with the amount of Rs12000
so I will earn some interest on it and 12th month I withdraw this 12000 and invested to PPF

What your opinion on it.