A Tennis Racket Manufacturer Produces Two Types of Rackets, Standard $x ^ { 2 }$

A tennis racket manufacturer produces two types of rackets, standard and competition. The weekly revenue function, in dollars, for x standard rackets and y competition rackets is given by R(x, y) = 54x + 2xy + 398y - 2 $x ^ { 2 }$ - 9 $y ^ { 2 }$ i) How many of each type of racket must be produced each week to maximize revenue?
Ii) What is the maximum weekly revenue?

A) i) 26 standard rackets and 26 competition rackets;
Ii) $5668
B) i) 25 standard rackets and 25 competition rackets;
Ii) $5675
C) i) 25 standard rackets and 26 competition rackets;
Ii) $5664
D) i) 26 standard rackets and 25 competition rackets;
Ii) $5677