Demonstrations of infants’ and toddlers' long-term memory have involved their repeating motor activities that they had seen or done earlier, such as reaching in the dark for objects, putting a bottle in a doll’s mouth,or pulling apart two pieces of a toy.
对标红的意思infer一下就是B的答案。
A是错在了你并不知道这个重要性,重要性讲的是 Maturation of the frontal lobes of the brain 而不是long-term memory
另外最后一句话讲了maturation可以支持long-term memory, 后面这句话的意思是这个long-term memory并不需要 verbal description,也就是用词汇来表达出来。