X and Y are two random variable and Z = X + Y. Let σ²x, σ²y and σ²z be variance of X, Y and Z. Then

X and Y are two random variable and Z = X + Y. Let σ²x, σ²y and σ

1.	X and Y are two random variable and Z = X + Y. Let σ²x, σ²y and σ²z be variance of X, Y and Z. Then
A.	σ²z = σ²x + σ²y
B.	σ²z ≤ σ²x + σ²y
C.	σ²z < σ²x + σ²y
D.	σ²z > σ²x + σ²y
Answer» B. σ²z ≤ σ²x + σ²y