Answer:
If you get bored inside, try going outside for some fresh air.
Step-by-step explanation:
The first line depends on the second line for it to make sense, thus it is joined by the use of a comma. The two sentences are not independent sentences, so they must not be separated by a period. You must not use a semi-colon when the two sentences are joined by a fanboy (the word ¨and¨ is a fanboy).