Concept:Substitute the given values into the algebraic expression and simplify using arithmetic operations.Explanation:Given a=3 and b=−7, substitute these into the expression:(a−b)25b+(a+b)2=(3−(−7))25(−7)+(3+(−7))2Compute the terms step by step:5(−7)=−35(3+(−7))2=(−4)2=16So numerator =−35+16=−19Denominator: (3−(−7))2=(3+7)2=102=100Therefore, the expression becomes:100−19=−0.19Answer:−0.19 (Option C)