Let the universal set be U={1,2,3,4,5,6}, and let
A={1,2,4},B={1,2,3,5},C={x∈U∣x2≤2}
.
In each of the following, fill in the blank with one or more of the symbols ⊂,⊆,=,=,∈, or ∈/ so that the resulting statement is true. For each blank, include all symbols that result in a true statement. If none of these symbols makes a true statement, write nothing in the blank.
{4,2,1}_____A