Let SSS be the set of divisors of 121212. Let TTT be the set of divisors of 181818. What is S∩TS \cap TS∩T?
{1,2,3,6}\{1, 2, 3, 6\}{1,2,3,6}
{1,2,3,4,6,12}\{1, 2, 3, 4, 6, 12\}{1,2,3,4,6,12}
The set of common divisors of 121212 and 181818.
{1,2,3,9,18}\{1, 2, 3, 9, 18\}{1,2,3,9,18}