(a)if the principal at the time of executing the power-of-attorney resides in any part of [India] [Substituted by Act 3 of 1951, Section 3 and Sch., for "the States" (w.e.f. 1.4.1951).] in which this Act is for the time being in force, a power-of-attorney executed before and authenticated by the Registrar or Sub-Registrar within whose district or sub-district the principal resides;