When the Pinecrest Animal Shelter, a charitable organization, was in danger of closing because it could not pay for important repairs, its directors appealed to the townspeople to donate money that would be earmarked to pay for those repairs. Since more funds were ultimately donated than were used for the repairs, the directors plan to donate the surplus funds to other animal shelters. But before doing so, the directors should obtain permission from those who made the donations. Which one of the following principles, if valid, most helps to justify the position advocated above and yet places the least restriction on the allocation of funds by directors of charitable organizations? ['People who contribute money to charitable organizations should be considered to be placing their trust in the directors of those organizations to use the money wisely according to whatever circumstance might arise.', 'People who solicit charitable donations from the public for a specific cause should spend the funds only on that cause, or, if that becomes impossible, should dispose of the funds according to the express wishes of the donors.', 'The directors of charitable organizations cannot allocate publicly solicited funds to any purposes for which the directors had not specifically earmarked the funds in advance.', 'Donors of money to charitable organizations cannot delegate to the directors of those organizations the responsibility of allocating the funds received to various purposes consonant with the purposes of the organization as the directors of the organization see fit.']