William and Charlotte Collins Divorced in November of Year 1

William and Charlotte Collins divorced in November of year 1. William moved out and Charlotte remained in their house with their 10-month-old daughter Autumn. Diana, Charlotte's mother, lived in the home and acted as Autumn's nanny for all of year 1. William provided 70% of Autumn's support, Diana provided 20%, and Charlotteprovided 10%. When the time came to file their tax returns for year 1, William, Charlotte, and Diana each wanted to claim Autumn as a dependent. Their respective AGIs for year 1 were $50,000, $35,000, and $52,000. Who has priority to claim Autumn as a dependent?

A) Charlotte.
B) Diana.
C) William.
D) They must negotiate amongst themselves.