The operating characteristic curves of three single sampling plans X, Y and Z with the same lot size and acceptance number are shown in the figure.Considering the above operating characteristic curves, the correct relationship of the plans with respect to sample size is

• A. Sample size of X < sample size of Y < sample size of Z
• B. Sample size of X = sample size of Y = sample size of Z
• C. Sample size of X > sample size of Y > sample size of Z
• D. Sample size of X > sample size of Y < sample size of Z