As [x]=−1 when x∈[−1,0). This makes denominator of first part 1+[x]=0. Hence, Interval [−1,0) must be excluded from domain set. ∴D(f)=R−[−1,0) Also at x=0 (which is part of domain), value of function is zero. i.e. f(0)=0 So option (mathrmd) is correct.