Let f(x,y) = ex + 5x - 18+ y. Complete parts (a) and (b) below.(3) Find f(1,8). Select the correct choice below and, if necessary, ll in the answer box to complete your choice. (b) Select the correct domain of f(x,y). O A. {(x,y)/x is any real number, y is any real number} O B. {(x,y) X > 0, y2 - 8} O c. {(x,y)/x is any real number, y 2 - 8} O D. {(x,y)|x > 0, y is any real number}