acetest series

Question

if L1 and L2 are two context sensitive language and L3 is a context free then

L=L1.L2-L3 is

a)regular

b)context free

c)context sensitive

d)recursive language

Comments

OPTION C

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L=L₁.L₂ ∩ (L₃)^'     // csl.csl=csl  , (cfl)^' is at least csl

csl ∩ csl =csl

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answr is recusive...

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the output language is at least CSL so recursive too. C and D both are answers. if answer is given only D then that's wrong answer.