Read the following context and choose the best option to answer the question.
Context: And I did n't care about anyone and just sat down each time the pain was unbearable . Then I 'll take a pack of ice and plaster it over my ankle . After work , we were all in such a good mood that some of us headed down to Geylang to get some food . Suzie , Mei and Ana were in uniform .
Question: Why did the author likely put ice on their ankle ?
Options: 
- Because they wanted to make a plaster cast for it .
 - Because suze , Mei and ana were still in uniform .
 - Because they were in such a good mood with their friends .
 - Because they must have injured it while they were at work .


Because they must have injured it while they were at work .