Doctor's ChoiceDiabetic Socks for Men, Seamless Socks with Non Binding Top, 4 Pairs, Large 9-12 & X-Large 13-15

Are they extra large calf?

Add clearly says 4 pair and picture shows 8 socks. Reviews complain that they received 4 socks not 4 pair. Which is it?

Where is the material sourced from?

I wear a mens size 10 1/2 x-wide shoe, to compensate for post foot surgery and not wanting anything tight on my feet. what size socks to get?