When targeting one or more segments... your choice should generally depend on several factors.
What is the existing level of competition and how good at serving customer needs are they? The greater the numbers and better they are able to meet customer needs the more difficult it will be for another business to also be a success.
How large is the segment, and how can you expect it to grow? (Note that a downside to a large, rapidly growing segment is that it tends to attract competition).
Do you have strengths as a company that will help you appeal particularly to one group of consumers? Firms may already have an established reputation.
Are you able to actual communicate with the segment?