1099-R and PA State Taxes

My Mother has a 1099-R for 2020 from a fixed annuity retirement savings.  The distribution code is 7D which is normal distribution/annuity payments from non qualified annuities that may be subject to tax under section 1411. It's asking for basis of retirement income.  Is this the gross distribution amount box 1 from 1099-R?

Thank you,