Mr. Amit signs on instrument in the following terms.
(i) "I promise to pay B or order Rs. 500"
(ii) "I promise to pay B Rs. 500, first deducting all other sums which shall be due to him"
(iii) "I promise to pay B Rs. 500 on D's death, provided D leaves one enough to pay that sum"
Which of the following are promissory notes?