--------you have the chance you had better make the best use

________you have the chance you had better make the best use of it.a.even though b.as long as c.if only d.now that为什么选择d?选择b和c表示条件状语不行吗?如果翻译成“只要你有机会，你就应该要好好利用。好像也是通顺的。