This piece picks up E-kKP as a knapsack problem in relation to the conventional and the simplest 2-approximation algorithm for the 0-1 knapsack problem. Taking account of the similarity between E-kKP and the multiple-choice knapsack problem, we mention how to produce two candidates onto the conventional and also how to obtain an optimal solution of LP-relaxed E-kKP that we require so as to produce the two candidates.