Consider the following statements (A) : Efforts are made to harness non-conventional energy sources for power generation. (R) : The conventional energy sources will be exhausted soon. Now select the answer from the following alternatives.

• A. Both (A) and (R) are true, but (R) is not the correct reason for (A)
• B. (A) is true, but (R) is false
• C. (R) is true, but (A) is false
• D. Both (A) and (R) are true and (R) is the correct reason for (A)