Many scientists have been probing psychological problems.

B
解析：本题考查的是对动词的认知。这句话的意思是：很多科学家都在探索心理学问题。本句中probe意为探索，时态是现在完成进行时，表示从过去某时开始一直持续到现在的动作，谓语动词构成have/has been doing。例如：I have been learning English since ten years ago．这十年来我一直在学英语。A．solving解决；B．exploring探索；C．settling解决；D．handling处理。选项B与划线处意思相近，例句：Both parties are exploring ways of settling the dispute．双方都在寻求解决争端的办法。