Answer:
Option D
Explanation:
Given a system of linear equation is x+λy−z=α,hx−y−z=α,x+y−λz=0
Note that given system will have a non trivial solution only if determined of coefficient matris is zero, i.e,

⇒1(λ+1)−λ(−λ2+1)−1(λ+1)=0
⇒λ+1+λ2−λ−λ−1=0
⇒λ+1+λ2−λ−λ−1=0
⇒λ3−λ=0=λ(λ2−1)=0
⇒λ=0orλ=±1
Hence , given system of linear equation has a non trivial solution for exactly three values of λ