Choice "A" is correct. Attribute sampling examines the rate of occurrence in a sample: the attribute either exists or does not exist. Therefore, attribute sampling is more useful for tests of controls, such as the examination of time cards for proper approval.
Choice "d" is incorrect. Attribute sampling is not appropriate for this substantive test of details. Classical variables sampling or Probability-Proportionate-to-Size (PPS) sampling, also known as dollar-unit sampling, is more appropriate.
Choice "b" is incorrect. Attribute sampling is not appropriate for this substantive test of details. Classical variables sampling or Probability-Proportionate-to-Size (PPS) sampling, also known as dollar-unit sampling, is more appropriate.
Choice "c" is incorrect. Attribute sampling is not appropriate for this substantive test of details. Classical variables sampling or Probability-Proportionate-to-Size (PPS) sampling, also known as dollar-unit sampling, is more appropriate.