How many positive integers A are there such that if we append 3 digits to the rightmost of decimal representation of A, we will get a number equal to 1+2+⋯+A?<spanclass=′latex−bold′>a)</span>0<spanclass=′latex−bold′>b)</span>1<spanclass=′latex−bold′>c)</span>2<spanclass=′latex−bold′>d)</span>2002<spanclass=′latex−bold′>e)</span>None of above