Read the following paragraph and choose the correct option f...

Read the following paragraph and choose the correct option for the question that follows:

I‘ve got a young friend, he‘s only 25, but he fits the bill perfectly. He‘s single and he‘s hungry. He‘s willing to start from scratch and, best of all, he isn‘t afraid of putting his nose to the grindstone for those 80-hour weeks. He decided to take the bull by the horns by going starting up his own business. He found a software developer who knew the internet inside out. This young man was also very ambitious. He left his safe job at the drop of a hat. They were both reaching for pie in the sky, and they were ready. They also were lucky. They founded a startup and got into the whole social networking business.

Adapted from: https://www.thoughtco.com/young-and-free-prerequisite-for-success-1210197 (Accessed on 01.21.2022)

The underlined idioms in the paragraph mean, respectively