Ans: b (60%) Ref: Park, 19th ed, p. 391Demographers are of the view that the demographic goal of NRR equals one can be achieved only if the CPR exceeds 60%Couple protection rate (CPR) is an indicator of the prevalence of contraceptive practice in the community.It is defined as the percent of eligible couples effectively protected against child birth by one or the other approved methods of family planning namely sterilization, IUCDs, condoms, OCPs.