In his search for the elusive memory trace karl lashley finally concluded that memory was the brain.

Karl Lashley was searching for the engram or the memory trace, a theoretical vehicle by which our memories would be physically stored in the brain, from 1929 to 1950. He believed that memory was stored in the particular area of the brain but instead through his experiments concluded that the memories were scatted, distributed across the brain. Today it is agreed that memories are distributed across the brain but the actual method of their storage is still debated and unknown.  

the 4th option is the answer

economic