Compute the 2021 standard deduction for the following taxpayers. If an amount is zero, enter "0".

a. Ellie is 15 and claimed as a dependent by her parents. She has $400 in dividends income and $3,440 in wages from a part-time job.

b. Ruby and Woody are married and file a joint tax return. Ruby is age 66, and Woody is 69. Their taxable retirement income is $12,430.

c. Shonda is age 68 and single. She is claimed by her daughter as a dependent. Her earned income is $240, and her interest income is $380.

d. Frazier, age 54, is married but is filing a separate return. His wife itemizes her deductions.