This question has options. Answer the question about text:

My mum wants to get rich which is why she got in to the property developing business . She has four properties all with a mortgage , one being the dream house my dad lives in , two she is renting out and the rent just covers the mortgage rates , and the fourth she lives in herself since splitting with my dad . Last year she was rushed to hospital with heart failure , now this was n't a clot that could be removed , this was something rare where her heart shrunk and would not pump .

What drives the mother 's income levels ?
pick from the following.
-- Selling and renting properties ..
-- Investing in hospitals ..
-- Running a hospital ..
-- None of the above choices ..
Selling and renting properties .