My boss has decided to send me to China to do a _____ course in Mandarin.
A. crash B. fast C. speed D. high-speed

Tell me the best answer and why.

Thanks

Question

My boss has decided to send me to China to do a _____ course in Mandarin. 
A. crash   B. fast   C. speed   D. high-speed

Tell me the best answer and why.

Thanks

Answer

A crash course in a particular subject is a short course in which you are taught basic facts or skills, for example before you start a new job.
^__^

Answer

A is the answer