True about Total Goitre Rate (TGR) is:

Ans: D. Goitres are classified as not visible, palpable and visible(Ref: Ghai 8Ie p519)The term 'endemic goitre' refers to a total goitre rate of >5 percent in a given community.Total goitre rate is an indicator of iodine deficiency, which causes brain damage and mental retardation.Endemic goiter is present when the prevalence of goiter in a defined population exceeds 5%.Endemic goiter is graded by the method of WHO.Screening estimates of iodine intake are usually derived from 24-hr urinary excretion values or urinary iodine concentration expressed in relation to creatinine concentration.