Here 1 is the right ans Q,R,C are set of rational , real and complex numbers respectively
Z is the set of integers, ie. positive, negative or zero
Q is the set of rational numbers, ie. represented by a fraction a/b with a belonging to Z and b belonging to Z *
R is the set of real numbers, ie. all numbers that can actually exist, it contains in addition to rational numbers, non-rational numbers or irrational
C is the set of complex numbers, ie. the set of real numbers R and all imaginary numbers I.