Read the given passage and answer the questions that follow.
Virtual learning refers to an environment where students study a digital-based curriculum
taught by instructors that lecture online via video or audio. This instruction can take place
either in a self-paced (asynchronous) environment or in a real-time (synchronous)
environment. There are many reasons why people choose virtual learning over instruction in a
traditional classroom. For example, the flexibility of virtual learning makes it an appropriate choice for full-time workers who would like to continue their education or cannot attend in-
person classes.
The virtual learning environment is also a good choice for people who enjoy self-learning.
Some virtual learning options have classes to attend at scheduled times, while others allow
you to learn at your own pace. With this self-paced option, you have a lot of autonomy with
the intensity and overall cadence of your learning while still enjoying the benefits of guided
lessons.
Virtual learning gives students access to coursework from anywhere, at any time, making
learning super convenient. Asynchronous classes also give an immense amount of flexibility
for lectures and studying. Even with the flexibility of the course, online courses are associated
with higher retention rates and graduation rates. A study conducted by Arizona State
University found that students taking virtual classes benefit from increased access and cost
savings of as much as 50 percent.
What is the most appropriate ANTONYM of the word ‘retention’ from the passage?