We strongly encourage discussion about the appropriateness of deceptive robots to determine what, if any, regulations or guidelines should ______ the development of these systems.
 
【正确答案】 C
【答案解析】 refrain“抑制,禁止”,强调抑制一种冲动,是正式用语,为不及物动词,后接介词from;restrain“抑制,约束”,指通过管束阻止某事发生,是及物动词,其习惯用法是restrain sb. (sth.) from doing;constrain“强迫,力劝”,是及物动词,强调强制性;contain“包含;控制”,强调控制性。本句的意思是要束缚the development of these systems(系统发展),故答案为C。