二者択一choice between only two things: 二者択一{にしゃ たくいつ}as between the two: どちらをとるかと言われればAs between the two approaches I'd much prefer the first. 二つの方法のうちどちらをとるかと言われれば私は前者を文句なく好む。between the two: 両者のうちで