两种都可。
elective/optional course： 选修课
Optional Elective Course： 任意选修课
例：
This course is a specialized optional course for overseas undergraduates who major in Chinese.
本课程是为汉语言专业本科的外国留学生开设的一门专业选修课。
Is that optional course as hard as everybody says?
那个选修课真的就像每个人说的那样难吗?
In college, English is a required course and psychology is an elective course.
在大学里，英语是必修课而心理学是选修课。
This is a elective course based on the study of the thoughts of Marx on historiography.
“马克思史学思想研究”是根据作者多年精心研究而设计的一门选修课程。
Distributional Electives
从课程的选修方式上，又分为必选课(Required),限选课（Distributional Electives）和任选课（Free Electives）
