A、5 hours. B、10 hours. C、17 hours. D、20 hours. C新闻提到，志愿者从早上5点工作到晚上10点，实行轮班制，早上5点到晚上10点一共17小时，故答案为C。

Many organizations around the United States hold canned food drives to help those in need. One Pennsylvania faith-based relief organization holds a drive with a twist: volunteers can the food themselves. Each winter, the Mennonite Central Committee sends a meat-canning truck on a tour of North America The truck is equipped with industrial-size pressure cookers, and each community it visits mounts an all-out effort to can as much meat as possible before the truck moves on to the next stop. About 30 people crowd into a small bam on a farm just outside of Freeport, Illinois. They work in shifts, from 5 in the morning until 10 at night. Over the course of two days, they cook and can over 6,300 kilos of turkey meat to be sent to hungry people all over the world.
1. What is the news report mainly about?
2. How long do the volunteers work in a small barn on a farm outside of Freeport?