Let f(x,y)=c(x+y)f(x, y) = c(x + y)f(x,y)=c(x+y) for 0≤x≤1,0≤y≤10 \le x \le 1, 0 \le y \le 10≤x≤1,0≤y≤1. What is the value of ccc?
111
0.50.50.5
222
0.250.250.25