Sam recently moved to a new city and has had to learn many new telephone numbers. Now he has difficulty remembering the numbers of his old friends in his former location. Forgetting is most likely due to

encoding failure

Explanation:

As in the question it is mentioned that Sam moved to a new city due to which he feels difficult to remember his old friend number. Now according to the tulving encoding principle, the retrieval would be successful the cue must be similar at the time of encoding

not  

cuba  

russia  

iraq  

el salvador  

explanation:

known as the land of volcanoes, el salvador has visit seismic tremors and volcanic movement. it is the main nation in central america that does not have a coastline on the caribbean sea. about portion of all salvadorans live in the wide open. they are poor and don't have power or running water in their homes. in 1525, pedro de alvarado, a lieutenant of cortés's, vanquished el salvador. el salvador, with alternate nations of central america, pronounced its freedom from spain on sept. 15, 1821, and was a piece of a league of central american states until the point when that association broke up in 1838.