LOGIC is:First diagram: 13 + 108 = 112 ⇒ 121 = 112Second diagram: 26 + 55 = 92 ⇒ 81 = 92Similarly,Third diagram: ? + 157 = 142 ⇒ ? + 157 = 196⇒ ? = 196 - 157⇒ ? = 39Hence, '39' is the correct answer.