Cassandra paid a day care center $20,000 during 2021 to care for her two 8-year-old twin sons while she worked as a data analyst for Omega Corporation, earning $80,000 during the year. Cassandra did not have any other income in 2021. What amount of child and dependent care credit can Cassandra claim in 2021? a. $10,000 O b. $6,000 O c. $16,000 d. $8,000 O e. $0