The correct option for the total lifetime cost for Toby to pay off his four loans is $31,616.
Computation of present value of the loans:
The given information is:
Principal = $ 6125
Interest rate = 5.3%


The present worth of all the loans is:

If he starts paying after four years, the worth of the loans by then is:

Therefore, the correct option is b.
To know more about the effective interest rates and loans worth, refer to the link below:
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