Clark, a widower, maintains a household for himself and his two dependent preschool children. for the year ended december 31, 2018, clark earned a salary of $32,000. he paid $3,600 to a housekeeper to care for his children in his home, and also paid $1,500 to a kiddie play camp for child care. he had no other income or expenses during 2018. before considering any limitation due to tax liability, how much can clark claim as a child and dependent care credit in 2018?