Answer:
The assumption made by Tom is an example of the context effect.
Explanation:
When a person is fed with some information about an event that happened in someone else's life in the recent past, he naturally tends to find the context behind the information and chooses to empathize with the person or be happy for the person depending on whether the information is positive or negative. In the given case, it is clear from what has happened with Ahmed that he must naturally be feeling bad. This belief that Tom has formed about Ahmed's possible state of mind is based on the negative 'context' of the event that has taken place in Ahmed's life.
It can be said that Tom is aware by experience or by observation that when someone who was close to you chooses to leave you all of a sudden, the consequences are mentally and emotionally painful. Based on the same belief that Tom already has about what Ahmed has gone through in his recent past, he assumes that Ahmed must be depressed. Hence, because Tom has made such an assumption beforehand, he tends to think that Ahmed actually appears to be in depression when he approaches him.