表达合作意愿的常用句型 — 国际贸易选择题

在撰写建立业务关系的函电时，若要委婉而正式地表达「希望与对方开展长期贸易合作」的意愿，下列哪个句子最符合外贸函电的惯用表达规范？ A. We want to make big money together with you soon. B. We wish to enter into long-term business relations with you on the basis of equality and mutual benefit. C. You must buy our products or we will not contact you again. D. Maybe we could do some business if you are free someday.