单项选择题
A．A. Genoa B. Hanoi C. Havana D. Kiev
A．in duplicate; in quadruplicate; in triplicate B．in quadruplicate; in triplicate; in duplicate C．in triplicate; in duplicate; in quadruplicate D．in duplicate; in triplicate; in quadruplicate
A．purity; thickness; stain B．stain; purity; thickness C．purity; stain; thickness D．thickness; stain; purity