A trust's secretary argues: 'The dispensary can be kept open only if we raise the consultation fee, since the trust's other course is to close it. The fee must therefore be raised.' An answer to which of the following questions would be of most use in judging the secretary's claim?

The secretary's 'therefore' rests entirely on there being no course but the two he names, and that is precisely what he has not shown. A donation, a rent from the trust's own property or a state grant would leave the dispensary open at the old fee and the argument in ruins, so the existence of a third source is the question to settle. When the fee was last raised bears on what members will think fair; the weekly attendance measures the dispensary's usefulness; and what neighbours charge would guide the size of any raise, but none of the three touches whether a raise is the only way.