Castle Inc. has the following information: Month Amount Units Cost A January $43,000 40,000 February $ 43,000 80,000 Month Amount Units Cost B January $ 86,000 February $120,400 68,800 137,600 Month Amount Units Cost C January $ 92,000 184,000 February $184,000 368,000 Indicate whether these costs are variable, fixed, or mixed. Cost A Cost B Cost C