Takes about a minute a piece, 15 cents extremely easy https://www.mturk.com/mturk/preview?groupId=2YEXHVKCJ011SUC7A10KUW69CN968G
They do but I'd just use your best judgement, I've never had a rejection from crowdflower out of the thousands I've done for them.
The first two did and I wasn't sure if I was supposed to be doing more than one, but they change...there aren't many different ones though