Answer: Similarity
Explanation:
Similarity principle of forming relationships states that relationships are formed due to the similarity in nature of individuals that tends to attract them towards each other form a relation. Same behavior, thinking, likes, dislikes ,opinions etc are the characteristics that are factors behind people forming relationship.
As the situation is question states that Talal and Hongwu belong to completely different culture but still persist similarity in opinions and experiences which makes them attract towards each other to become friends.
Thus, the situation is based on similarity principle for establishing relationship.
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