A colon is best used to connect two independent clauses when Select one:
1.the second clause is an elaboration of the first clause.
2.the first clause is the cause and the second clause is the effect.
3.the first clause contains a list.
4.the second clause contains a quotation.

1.   the second clause is an elaboration of the first clause.

Explanation:

Examples:

The local temperature where I live is quite high: in July it remained consistently in the 90 degrees range, which was an improvement on the current temperatures, which are stuck in the 100 degrees range.  

The purpose for answering your question is twofold: (1) to help you understand; and (2) to show you how "" I am.

judy jones is an attractive woman who receives attention from many men throughout the story.   despite her beautiful appearance, she is superficial and callous.   she is an aggressive woman who goes after any man she desires but she is not happy.   she is fickle and is never satisfied.   her beauty is only skin deep.   dexter breaks down because he knows his dreams are unattainable.   he believes that wealth and physical beauty are what will make him happy.   he soon realizes that she has lost her attractive looks.   it is not all what he had planned.

its confident and professional