In reviewing the image below, what is the minimum value for this function?

In reviewing the image below, what is the minimum value for this function?
 
   
  a.
  8
   
  b.
  0
   
  c.
  1
   
  d.
  1

Q. 2

Which of the following functions yields the shape shown below?
 
 
   
  a.
  f(X, Y) = X² + Y²
   
  b.
  f(X, Y) = Xsin(2Y) + Ysin(2X)
   
  c.
  f(X, Y) = X²  Y²
   
  d.
  f(X, Y) = Xsin(5X) + Ysin(5Y)

Q. 3

In reviewing the image below, the point (0, 0, 0) is a(n) __________ for the given concave function.
 
 
   
  a.
  local maximum
   
  b.
  local minimum
   
  c.
  convergence point
   
  d.
  endpoint

Q. 4

In reviewing the image below, which of the following functions is most likely to yield the above shape?