21. Abbey and Bob are married. Abbey contributed 70% of the funds to purchase an apartment building, and Bob contributed 30% of the funds to purchase the building. Abbey and Bob took title to the apartment building as joint tenants with rights of survivorship. Indicate the portion of the apartment building includible in Abbey's gross estate on her death. . The entire value of the apartment building will be included in her gross estate because a joint tenant may enjoy the entire property subject to use of the other tenant b. 70% of the value of the property will be included in her gross estate because that is the portion of the purchase price contributed by Abbey c. 50% of the value of the property will be included in her gross estate because Abbey and Bob are married, and are the sole joint tenants