Test Jean Piaget's theory of cognitive development

1st QUESTION: What is the most important cognitive achievement of the sensorimotor stage (0-2 years)?

They cannot understand object permanence
They are unable to use language
They are still very self-centered and have a hard time seeing things from other people's perspective
They can only think about abstract ideas

As the result of a constant interaction between innate abilities and environmental influences
As a process that depends exclusively on genetic inheritance
As a development that occurs without a fixed order of stages
As something that is not related to moral understanding