A parent who keeps a son’s room intact even though he’s been happily married and in his own home for five years is exhibiting which defense mechanisms?

Denial

Explanation:

Denial refers to a tendency among humans, w.r.t the inability to come to terms with reality, wherein an individual exhibits such behavior that creates a sense of fake hope of something's existence, despite knowing that no such thing exists in real.

Denial mechanism is commonly observed when an individual loses a loved one. Till a certain time period, the bereaved is unable to come to terms with the non existence of the person, refusing to believe and accept what is evident.

It acts as a kind of blockage of external events from the mind's awareness state. Such behavior acts as a defense mechanism in the sense that, individuals try and protect themselves from anxiety or guilt.

In the given case, the parent, out of his/her attachment, affection and fondness with the son, derives fake solace in maintaining his room as before, perhaps in false hope that the son may arrive anytime and recreate the same old effect, which was delightful to the parent, which is being badly missed currently.

is there a year set? the question is incomplete