The total pattern function for rectangular aperture f(x, y) if f(x) and f(y) are separable is given by ____

• A. f(x, y)=f(x) f(y)
• B. f(x, y)=f(x)+f(y)
• C. f(x, y)=f(x)/f(y)
• D. f(x, y)=f(x)-f(y)