That depends on which operating system you're looking for, the purposes you need it for and where you live.
If we're assuming an average user with no special requirements for programming or other specialised tasks then I'd recommend Windows 10.
Windows 10 is the most popular OS (Operating System) and is widely supported by the community of you run into trouble.
You can find a liscenced copy from their website, which you may need to change to your locale and most computer shops will sell copies too, including online companies like Amazon, but if you're unsure then Microsoft is the best bet.
https://www.microsoft.com/en-gb/store/d/windows-10-home/d76qx4bznwk4/1NT3
I hope this helps.
Currency I think. It's given in exchange for an item.
Answer:
The correct answer is the letter b. Efficiency refers to maximizing the size of the pie; equality refers to distributing the pie fairly among members of society.
Explanation:
Efficiency is about maximizing production while minimizing costs, ie producing as much as possible with available resources. Equality refers to the distribution of production, that is, the division into economically considered fair parts of what was produced among the agents of society. In the example, efficiency would be to produce the largest pie possible given the existing resources. Equality would be the distribution of the pie considered socially fair.