Castle Incorporated has the following information about three costs, A, B, and C: Month Cost A January Amount $ 82,000 February $ 114,800 Units 65,600 131,200 Month Amount Units Cost B January $ 41,000 40,000 February $ 41,000 80,000 Month Amount Units Cost C January $ 84,000 168,000 February $ 168,000 336,000 Required: Indicate whether these costs are variable, fixed, or mixed. Cost A Cost B Cost C