If a Charity Is Already Exempt from Estate Taxes, What

If a charity is already exempt from estate taxes, what is the purpose of setting up a charitable trust?

A) It allows a charity to benefit from your assets during your lifetime while allowing you to retain the use of, or the income from, the asset.
B) It allows a charity to receive a credit from the government for the charitable institution.
C) It allows the trust to generate more income than a charity could generate.
D) It provides tax credits to the charitable institution.