If gcd(a,b)=1\gcd(a, b) = 1gcd(a,b)=1, which of the following statements MUST be true?
gcd(a+b,ab)=1\gcd(a+b, ab) = 1gcd(a+b,ab)=1
gcd(a−b,ab)=1\gcd(a-b, ab) = 1gcd(a−b,ab)=1
Both (a) and (b)
Neither (a) nor (b)