If GCD(a,b)=7\text{GCD}(a, b) = 7GCD(a,b)=7 and a,b>0a, b > 0a,b>0, which of the following is true regarding GCD(3a,3b)\text{GCD}(3a, 3b)GCD(3a,3b)?
777
141414
212121
494949