What cables to use.

HDMI.

May or may not make a sonic difference over optical (depends upon the quality of the TV/cable provider), but you will be good to go with any improvements down the line.

Think they are around the same price, so HDMI.

If you shop Amazon or Walmart and would like something inexpensive look @ Monoprice HDMI’s.

This said, I'm not really into TV but the Monoprice HDMI I use to connect a DVD player works fine (picture/sound) with our TV.

DeKay

@dawg007 

You’re in the right place, sir. Dekay that answered you is a respected member, I trust his take on it!

In the end of course it’s your preference.

Nice family picture, enjoy!

Optical cable will outperform hdmi in long distance application. I have 30ft long hdmi cable connecting my main TV with smaller TV in my tool room in my basement and the quality is pretty low. When I tried 5ft hdmi connection just to check difference,  it was significantly better. 

15’ should not be a problem for a decent HDMI cable.

I’ve used a 30’ Monoprice a few times to directly connect our Internet modem to the cable box (usually run WiFi, but it craps out from time to time) and it worked fine.

This said, our previous and current TV cap out @ 1080P, and like I said I’m not picky about TV (it just needs to look/sound OK).

DeKay

Plus 1 dekay 

Amazon has a 15’ hdmi for $16.99 with a 10% off coupon that should do the trick.

4K HDMI Cable 15FT,Highwings 2.0 High Speed 18Gbps HDMI Braided Cord-Supports (4K 60Hz HDR,Video 4K 2160p 1080p 3D HDCP 2.2 ARC-Compatible with Ethernet PS4/3 4K Projector Game Monitor ect-Grey https://a.co/d/ihUojrE

All the best.