You must choose one exclusively from the following options.alternative指的是几个可供替换的方案/选项.其实简单写成：You must/(are required to) choose one of them.You are expected/encouraged to choose on...
You must choose one exclusively from the following options.alternative指的是几个可供替换的方案/选项.其实简单写成：You must/(are required to) choose one of them.You are expected/encouraged to choose on...