Ans. is 'c' i.e., Ic International death ceificate The basis of moality data is death ceificate. For ensuring national and international comparability, it is necessary to have a uniform and standardized system of recording and classifying deaths. For this purpose WHO has recommended international death ceificate. Consist of four lines: Line Ia: Disease or condition directly leading to death Line Ib: Antecedent/ underlying cause Line Ic: Main antecedent / underlying cause Line II: Other significant conditions contributing to death but not related to disease/ condition causing it Example of a death ceificate: Line Ia: Renal failure Line Ib: Diabetic nephropathy Line Ic: Diabetes mellitus Line II: Hypeension Concept of underlying cause, Line Ic is the most impoant line in death ceificate, thus also known as `Essence of Death Ceificate'.