Taxpayer inherited IRA from Grandmother. Her share of the IRA is in her name and name of deceased. Advisor also created a Roth IRA in the name of the taxpayer so Trustee to Trustee. DOD was Dec 2020.

$8,000 was distributed in 2021 with 1099-R:

Line 1 = $8,000   Line 2a $8,000  Line 2b Marked X for Taxable amount not determined

Withheld for Fed & State   Line 7 = 4

No contributions and only $8,000 distribution, 2021 RMD Basis Value = $50,104

Advisor also provided statement that $6,000 Roth IRA contribution was made in 2021 in taxpayer's name. Roth Account Value as of 12/31/21 - $5,978.92.

Based on these facts, is all the $8,000 taxable?

Thanks for the help in advance!