I NEED HELP ASAP!!!!! -THIS IS K12 8TH GRADE ENGLISH

Which sentence uses a formal style that is appropriate in an informational piece of writing?

Kelly, a big dog lover, decided to start a pet-sitting business, but then realized she hated having to walk the dogs, especially when it rained.


If you launch a product at a trade show, you better not flake on filling orders for your customers.


To become an entrepreneur, you not only need an idea but a business plan that sets goals and objectives for the business.


Entrepreneurs need to get a clue about their start-up costs and know someone who can foot the bill for them until the business takes off.