Implicit memory is to explicit memory as is to context-dependent memory; state-dependent memory automatic processing; effortful processing short-term memory; long-term memory proactive interference; retroactive interference

I think the correct answer would be the second option. Implicit memory is to explicit memory as automatic processing is to effortful processing. Implicit memory can be also related to automatic processing as it is the type of long term memory that is used and being acquired with the unconscious mind. It uses experiences of the past to remember certain things without actually thinking of these experiences. On the other hand, explicit memory is related to effortful processing. It uses the conscious mind for recalling experiences of the past like remembering who are the people you are with the other night or recalling the animals that you saw in the zoo.