A. A single plus symbol means .must be covered by each tester of the supplier'. double plus symbol means
"must be tested for applicability by me tester of the contractor".

B. Single plus symbol means .should be applied by the tester of the suppler", double plus symbol means
"can be applied by the tester of the suppler".

C. The tester of the suppler must choose an appropriate combination of methods and explain Ms choice.
The methods with a double plus symbol should be given higher consideration

D. Single plus symbol means .must be applied by the tester of the suppler", double plus symbol means 'can be applied by the tester of the supplier