An example of a volunteer opportunity within one's community might be join the us army or us navy. sign up for the peace corps. serve at a homeless shelter. take part in teach for america.

I believe the answer is: serve at a homeless shelter.

Volunteer refers to the act of doing something that benefit other people without expecting nothing in return. All example above could be considered to be volunteer activities (maybe except for joining army, depending on your intention). By the ones that happen on local level only serving at homeless shelters.

Teach for america occurs on national level. Joining army and peace corps happen on international level.

The correct option is serve at a homeless shelter

Serving at a homeless shelter is an example of voluntary service in the community as it involves giving back to the community by serving the less fortunate that have found themselves in the dire need for shelter