If gcd(a,b)=d\gcd(a, b) = dgcd(a,b)=d and gcd(c,d)=1\gcd(c, d) = 1gcd(c,d)=1, which of the following must be true?
gcd(a,b,c)=1\gcd(a, b, c) = 1gcd(a,b,c)=1
gcd(ac,bc)=cd\gcd(ac, bc) = cdgcd(ac,bc)=cd
gcd(ac,b)=d\gcd(ac, b) = dgcd(ac,b)=d
gcd(a,c)=gcd(b,c)\gcd(a, c) = \gcd(b, c)gcd(a,c)=gcd(b,c)