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Which of the following topological spaces is(are) sequentially compact?

Select ALL that apply.

The Cantor set.

$[0,1]\times [0,1]$ with order topology induced by the Lexicographic order.

The order topology on the first uncountable ordinal $\omega_1$.

$\{1/n:n\in\mathbb{Z}-\{0\}\}\cup\{0\}$.