Form 1116 Foreign Tax Credit worksheet - wants the "Adj Asset Basis for Investments generating foreign income". Where do I find this and for what date for the asset basis?

Smartcheck highlights an error on Form 1116 worksheet, asking me to include the "adjusted basis of investment assets generating foreign income" on line 4b of the worksheet.  I do not have the asset values - form 1099 supplemental Foreign Tax Paid schedule only has foreign tax, income and QDI???  A 2019 post response says to include Foreign Income as a % of Total Income but questions are asking about Adj Asset basis ... what is needed and where do I get that information (and what date for asset basis is needed - 12/31/19?)??  This needs more guidance in TT please.