A、English for doctors. B、English for lawyers. C、English for reporters. D、English for businessman. D短文的结尾处提到最受欢迎的ESP课程是商务英语，故选D。

There are three groups of English learners: beginners, intermediate learners, and learners of special English. Beginners need to learn the basics of English. Students who have reached an intermediate level benefit from learning general English skills. But what about students who want to learn specialist English for their work or professional life? [23]Most students, who fit into this third group, have a clear idea about what they want to learn. A bank clerk, for example, wants to use this specialist vocabulary and technical terms for finance. But for teachers, deciding how to teach specialist English is not always so easy. For a start, the variety is enormous. Every field from airline pilots to secretaries has its own vocabulary and technical terms. [24]Teachers also need to have an up-to-date knowledge of that specialist language, and not many teachers are exposed to working environments outside the classroom. These issues have influenced the way specialist English is taught in schools. This type of course is usually known as English for Specific Purposes or ESP and there are ESP courses for almost every area of professional and working life. In Britain, for example, there are courses which teach English for doctors, lawyers, reporters, travel agents and people working in the hotel industry. [25]By far, the most popular ESP courses are for business English.
23. What do we know about the learners of special English?
24. What has influenced the way of teaching specialist English in schools?
25. According to the speaker, what are the most popular ESP courses in Britain?