A executed a demand promissory note in favour of B for an ascertained sum. Though the parties had…

Section 80 of the Negotiable Instruments Act provides that where no rate of interest is specified in the instrument, interest is payable at eighteen per cent per annum. By writing 18% into the note, B only stated the rate the law already supplies, so there is no material alteration under section 87 and the note is not void, voidable or incomplete: "None of the given options is correct". An unauthorised insertion that increased the liability, such as a higher or monthly rate, would be a material alteration making the note void.