Which of the following pairs of (a,b)(a, b)(a,b) satisfy GCD(a,b)=3\text{GCD}(a, b) = 3GCD(a,b)=3 and a+b=15a+b = 15a+b=15?
(3,12)(3, 12)(3,12)
(6,9)(6, 9)(6,9)
(9,6)(9, 6)(9,6)
(12,3)(12, 3)(12,3)