Let X={a}X = \{a\}X={a}, Y={b}Y = \{b\}Y={b}, and Z={a,c}Z = \{a, c\}Z={a,c}. Find the union X∪Y∪ZX \cup Y \cup ZX∪Y∪Z.
{a,b}\{a, b\}{a,b}
{a,b,c}\{a, b, c\}{a,b,c}
{a,a,b,c}\{a, a, b, c\}{a,a,b,c}
{c}\{c\}{c}