For each of the following sentences, find an example in which the claim of the sentence obtains:
(a) The sets C1 and C2 are approachable by Player 1, but the set C1 ∩ C2 is excludable by Player 2.
(b) The set C1 is approachable by Player 1, the set C2 is excludable by Player 2, and the set C1 \ C2 := C1 ∩ (C2) c is excludable by Player 2.
(c) The sets C1 and C2 are excludable by Player 2, but the set C1 ∪ C2 is approachable by Player 1.