1. having a LAN cable between the PC and the router is always the best option.
2. WiFi adapter is an ok choice in my opinion if it's really good quality.
3. Powerline adapter is a massive double edged sword because at certain situations it will work perfectly and in many other situations it won't work at all. Also it takes a good ammount of electrical knowledge to know when will this be a good option.
4. Extenders - worst option of them all.