Step 1: Introduce the given information Given, Confidence level, C = 90% = 0.90 Margin of error, E=3%=0.03 Step 2: Calculate the sample size (expression) Using formula, -P) [+] Sample size, n = p(1-p)x Here, Level of significance, α = 1-C = 1-0.90 = 0.10 At a = 0.10 the critical value is Z = 1.645 (Using Excel = NORM.S.INV(1-0-10)=1.645) 2 Since here no estimate for the population proportion (p) is provided, so we use p = 0.5. Therefore, sample size is, n=0.5x(1−0.5)x| 1.645 = (0.5)²x 0.03 1.645 0.03 The correct option is (B) Solution The correct option is (B)