What are the subsets of a b c and d?

The subsets of a b c and d are:

* {} (the empty set)

* {a}

* {b}

* {c}

* {d}

* {a, b}

* {a, c}

* {a, d}

* {b, c}

* {b, d}

* {c, d}

* {a, b, c}

* {a, b, d}

* {a, c, d}

* {b, c, d}

* {a, b, c, d}