पर्यावरणीय गुणवत्ता में परिवर्तन के कारण कल्याण (welfare) में होने वाले परिवर्तन को सैद्धांतिक रूप से निम्नलिखित में से किस फलन द्वारा मापा जाता है?

Which of the following statements are NOT true in relation to methods of environmental valuation? a) Contingent valuation method is one of the methods of environmental valuation. b) Contingent valuation method is a direct method of environmental valuation. c) Contingent valuation method is an indirect method of environmental valuation. d) Travel cost method is a direct method of environmental valuation.

Given below are two statements, one labeled as Assertion (A) and the other as Reason (R): Assertion (A): According to Hardin's 'Tragedy of the Commons' model, open-access resources are overexploited by the public. Reason (R): In the case of open-access resource usage, marginal private benefit exceeds marginal private cost. In light of the above statements, choose the correct answer from the options given below: