Answer:(a) It occurs when the strength of a memory deteriorates over time because of the presence of other (new) memories that compete with it.
Explanation:
What is interference?
-Interference is the theory which describes how and why does forgetting things takes place in our long term memory. Interference is how some acquired memories tends to interfere with us acquiring other memories.
-Interference is said to occur when there is a competition in our memories which result to us forgetting other memories completely as compared to others as a result of interference we find it very hard to bring some memories stored in the long term memory to the short term memory.
-There are moment where you find yourself confusing two memories and not being sure which one is which especially when they seem to share some similarities for example if someone ask you if you took your lunch to work last Friday it would be hard to recall because this is associated with other many days in which you take lunch.