Passage Summary: Carl's sells only two decaf options: French Roast and Mocha Java. Yusef only serves decaf and usually buys from Carl's. Since the coffee he served wasn't French Roast, it had to be Mocha Java, provided he hasn't changed where he shops.

Conclusion: If Yusef still sources all his coffee from Carl's, the coffee he served last night must have been Mocha Java.

Reasoning: Carl's only sells two types of decaf (French Roast and Mocha Java), Yusef only serves decaf, and the coffee served was definitely not French Roast.

Analysis: The argument utilizes a process of elimination within a restricted set of two possibilities. To parallel this, look for a structure where a set is defined as containing only two members (X and Y), one member (X) is ruled out by a specific characteristic, and the conclusion states that if the subject is still limited to that set, it must be the other member (Y). The logic is essentially: 'If it's in the set and it's not X, then it must be Y.' Pay close attention to the conditional 'if' in the conclusion, as the argument doesn't claim it *is* Mocha Java, but rather that it must be *if* the source hasn't changed.