$($Table$)$ The table shows coffee and tea units produced for the United States and Japan. The opportunity costs are

$\backslash$table$[[,$United States$],[$Coffee$,25,20,15,10,5,0,],[$Tea$,0,2,4,6,8,10,],[,,,,$Japan,,,$],[$Coffee$,58,52,44,34,20,0,],[$Tea$,0,12,24,36,48,60,]]$

a$)$ increasing for the United States and Japan.

b$)$ constant for the United States and increasing for Japan.

C$)$ increasing for the United States and constant for Japan.

d$)$ constant for the United States and Japan.