A unit offers six training courses, including abcdef, and employees voluntarily sign up for them. According to statistics, there are four courses that employees choose: a+f, d+f, a+c+e and B+C+F. After all the training, the exams will be arranged in a unified way. In order not to affect the job requirements, I will take exams for six consecutive days from 65438+ 10 to 10, and only take one exam every day.

A.2 types

B.4 types

C.8 kinds

D. 12 species

The first step is analysis. This question examines the problem of permutation and combination.

The second step, according to the meaning of the question, is divided into two situations, one is 4-9 days, and the other is 5- 10 days. Each category is listed. Because each employee does not take exams for two consecutive days, it can be combined with the employee's choice, including: F, E, B, A, D, C; C, D, A, B, E, F, the total number of species is 2×2=4.

Therefore, choose option B.