Step-by-step explanation:
(a) subsets are {apple}, { }
(b) subsets are {1}, {2}, {1,2}, { }
proper subsets are {1}, {2}
(c) subsets are
{a}, {b}, {c}, {a,b}, {a,c}, {b,c}, {a,b,c}, { }
proper subsets are {a}, {b}, {c}, {a,b}, {a,c}, {b,c}
(d) subsets are {1},{2},{3},{4},{1,2},{1,3},{1,4},{2,3},{2,4},{3,4},{1,2,3},{1,2,4},{1,3,4},{2,3,4},{1,2,3,4},{ }
proper subsets are {1},{2},{3},{4},{1,2},{1,3},{1,4},{2,3},{2,4},{3,4},{1,2,3},{1,2,4},{1,3,4},{2,3,4}
