As far as the conditions you expressed are concerned, you can only choose 3,500 yuan, because the loan will be repaid 700,000 yuan every month after 30 years, and 30 years is the upper limit, and it can't be longer. This is the repayment method according to the equal principal and interest.

If it is the repayment method in average capital, your initial repayment period is longer than this, but this repayment method is decreasing, that is, the monthly repayment amount is decreasing.

And the repayment amount depends on your income certificate, which generally does not exceed 50% of the income stated in your income certificate. Banks should control risks.