The correct option is C one-one and onto
f(x)=x−(−1)x
f(x1)=f(x2)
⇒x1=x2
In the above function
f(2n)=2n−1 and f(2n−1)=2n
nϵN.
Hence the above function is one one function.
Also, each point in the co-domain is the value of f(x).
Hence the above function is one one and onto function.