Which of the following is directly related to the assessment of donor's tax?

The assessment of donor's tax is primarily determined by the value of all gifts given. This is because donor’s tax is levied based on the value of the gifts transferred from the donor to the recipient within a particular tax year. The tax is calculated on the total amount of these gifts, with a few exclusions or deductions allowed.

In assessing donor's tax, the other factors such as the recipient's income level, the donor's total net worth, and the relationship between the donor and recipient do not directly influence the taxable amount itself. Instead, they might play a role in how gifts are perceived for other tax implications or exemptions but do not impact the direct assessment of donor's tax. Therefore, understanding the total value of gifts given is crucial for accurately determining the tax owed.