The question is incomplete and the full version can be found online.
Answer: Ruby’s purpose in life
Step-by-step explanation:
The idea that sewing is Ruby´s ministry refers to her purpose in life because that word applies to a calling some people feel to follow a certain path to achieve a specific purpose in life, most likely connected to religious beliefs.
It doesn´t mean that Ruby acts this way because it´s what´s expected of her. Furthermore, saying that Ruby chooses to treat her customers fairly would be incorrect, because her not even charging them is beyond fair treatment. And saying that Ruby’s actions are led by a desire to share her profits would be incorrect, because she wants to help others by not charging for her service, not by giving them money.