单选题 According to the passage, the dynamics of small group economies differ from those of large group economies in that

• (A) the members of small groups tend to have a greater degree of social regularity than the members of large groups
• (B) people in small groups carry an advantage in the arena of exchange because they are tied by social obligation
• (C) the manufacturer of a commodity in a small group economy is more likely to be known by the members of the group
• (D) the people who contribute to the production of a gift are less essential to small groups than those who exchange commodities are in large groups
• (E) a system of social obligation diminishes the number of parties necessary to a gift-giving transaction