Shalonda and Bridgette are neighbors. They run into each other when they walk their dogs, exchange small talk, but don't really self-disclose with each other. This is an example of a friendship of receptivity.
Across cultures, friendships are a matter of choice.
Lauren befriended Jack because he is a math genius and she is struggling in her math class. Jack is filling a security need for Lauren.
Bryant and Cayla tell say "I love you" frequently and often find themselves finishing each other's sentences. They would be considered an independent couple.