The tаble belоw summаrizes а prоductiоn process in which input is used to produce output. Input Output Total physical product Average physical product Marginal physical product 0 0 0 XX XX 1 15 15 15 15 2 27 27 13.5 **B** 3 36 36 **A** **C** 4 42 42 10.5 6 What is the value for APP that should appear in cell **A**?