Question : Simplify the given expression. $\frac{x^3+y^3+z^3-3 x y z}{(x-y)^2+(y-z)^2+(z-x)^2}$

Option 1: $\frac{1}{3}(x+y+z)$

Option 2: $(x+y+z)$

Option 3: $\frac{1}{4}(x+y+z)$

Option 4: $\frac{1}{2}(x+y+z)$

Question : Directions: In the following question, select the related letters from the given alternatives.
NA : SF :: OB : ?

Option 1: IJ

Option 2: TG

Option 3: RG

Option 4: TH

Question : Directions: Select the related code from the given alternatives.
ST : ZM :: KR : ?

Option 1: KR

Option 2: RK

Option 3: LR 

Option 4: LK

Question : Directions: In the given question, select the related letter from the given alternatives.
C : I :: D : ?

Option 1: L

Option 2: M

Option 3: N

Option 4: O

Question : Directions: Select the related code from the given alternatives.
MP : PN :: QR : ?

Option 1: PT

Option 2: TP

Option 3: LM

Option 4: NR