Question

[Trần khánh chi]

all positive integers appear in the sequence 1,2,2,3,3,3,4,4,4,4,..,and each positive  integer k appears i the sequence k  time . in the sequence, each term after the first is greater than or equal of the term before it. if the intrger  12 first is appears in the sequence as the nth term ,what is the value of n ?

A)62       B)66       C) 65      D)67        E)64