The stimulus gives us a principle, which we need to correctly apply. To do this, we have to understand what possible valid outcomes the principle can yield. The principle gives us two necessary conditions for promise-breaking to be wrong: (1) breaking the promise must harm the person to whom the promise was made (the "promisee"), and (2) everyone who learns about the broken promise must lose confidence in the promisor's ability to keep promises.

_wrongbreak promise → harm promisee
_wrongbreak promise → _{lose confidence in promisor}everyone who learns

Since we're dealing with a sufficient-necessary conditional relationship, there are two ways we can validly apply the principle. The first is to deny one or both necessary conditions to deny the sufficient condition. So if we can say a broken promise didn't harm the promisee and/or didn't cause someone who learned about it to lose confidence in the promisor, we can say that it wasn't wrong to break the promise.

The second way is to affirm the sufficient condition to affirm both necessary conditions. If it was definitely wrong to break a promise, that lets us infer that breaking the promise harmed the promisee and caused everyone who learned about it to lose confidence in the promisor. The correct answer must follow one of these two patterns, because these are the only valid ways to apply the principle.