The option that will save you money over the life of your loan is:
d) making larger payments than required.
Making larger payments allows you to pay off the principal more quickly, which reduces the amount of interest you will pay over the life of the loan.
The other options—taking a loan with a longer term, taking a loan with a higher APR, or making a smaller down payment—will generally result in higher overall costs or interest paid over the life of the loan.