equity means you OWN something---all you get for a tax payment is a cancelled check or credit card receipt. If you mean which tax has the least EQUALITY, there is no such thing as a FAIR tax--some will pay more and other less no matter how you structure a tax.
The tax that is considered the LEAST EQUAL (most unfair) is sales tax on food. Everybody eats about the same amount and pays the same amount in tax, no matter their income.
Some states have helped correct this problem by not charging sales tax on food.
But Mike and shipwreck are correct, too.
no tax has any equity.
no tax has equity I think you need a dictionary.
which of the following tax has the least equity