Determine the total allowable 2018 earned income credit in each of the following situations:

a.	Rina is single and earns $6,800 in salary for the year. In addition, she receives $2,200 in unemployment compensation during the year.
b.	Lachlan is single with one dependent child. During the year, he earns $8,000 as a waiter and receives alimony of $10,000 and child support of $5,000.
c.	Zorica is a single parent with two dependent children. She earns $19,000 from her job as a mechanic. She also receives $3,000 in child support from her ex-husband.
d.	Elliot and Pam are married and have three dependent children. Elliot and Pam earn $12,000 and $9,000 from their jobs, respectively. They receive $800 in interest and $1,000 in dividend income. Assume the taxpayer files a joint return.