Read the following conjecture and proof. Conjecture: The sum of three consecutive whole numbers is divisible by 3. Proof: Let Equation 020, Equation 018, and Equation 019represent the consecutive whole numbers. The sum of the three numbers is Equation 020. 3 is a factor, so the sum is divisible by 3. The proof is Question 7 Select one: a. invalid: It has used circular reasoning. b. invalid: It didn't reach the desired conclusion. c. valid. d. invalid: It cannot be determined whether is divisible by 3. Clear my choice