Let \(t\ge 2\) and \(k\ge 1\) be integers. A t-regular partition of a positive integer n is a partition of n such that none of its parts is divisible by t. Let \(b_{t,k}(n)\) denote the number of hooks of length k in all the t-regular partitions of n. Recently, the first and the third authors proved that \(b_{3,2}(n)\ge b_{2,2}(n)\) for all \(n\ge 4\) , and conjectured that \(b_{t+1,2}(n)\ge b_{t,2}(n)\) for all \(t\ge 3\) and \(n\ge 0\) . In this paper, we prove that the conjecture is true for \(t=3\) .