Q:Read the following article and select the best answer. Article: Instagram is containing so many photos of food--now a pop-up diner in London is taking advantage of this new trend by letting people settle the bill for their meals simply by uploading photos of their dishes to social networks. I always thought people's taking pictures of their food was kind of silly, but at this new pop-up restaurant in the UK, I'd probably do it too. 'The Picture House' is the world's first pay-by-photo restaurant--you order, click a photo of the food, share on Instagram and eat for free! The restaurant belongs to frozen food giant Birds Eye, who came up with the idea to cash in on people's addiction with photographing food and sharing the pictures online. They conducted a survey and found out that more than half of the British population regularly took pictures of their meals. So they realized it was a better way to advertise their new dining range. The pop-up diner was open in Soho, London for three days in May, and is now moving to other major UK cities. They serve two-course meals that customers don't have to pay for, if they photo and Instagram it. The restaurant is a part of Birds Eye's 'Food for Life' campaign, a new marketing project that aims at changing the way people look at frozen food. "Taking photos of food enables people to show off and to share their mealtime moments--from the everyday to the special," said marketing director Margaret Jobling. The reaction to The Picture House has been great so far. And the pay-by-picture concept has proven to be an effective way. Alternative payment methods are actually gaining popularity among a lot of businesses. Last year, in a cafe in Germany customers pay by how much time they spend there, not by what they eat. Question: Instagram probably is _ . - a restaurant free of charge - a campaign of "Food for Life" - a new marketing project - a program used to share photos
A:
a program used to share photos