Read the following passage and mark the letter A, B, C or D to indicate the correct word or phrase that best fits each of the numbered blanks.

Earth Hour is a movement organised by the World Wildlife Fund (WWF). The event takes (13) annually around the world. It encourages everyone to turn (14) non-essential electric lights, for one hour, from 8:30 to 9:30 p.m. on the last Saturday of March. The initiative was proposed in 2004 in Australia, but the idea of a (15) movement was developed in 2006 under the name 'The Big Flick". In 2007, the first Earth Hour was held on 31 March in Sydney, Australia at 7:30 p.m., local time. Later in October 2007, a similar event called 'Lights (16) was held in San Francisco. (17) the success of these events, the organisers decided to hold Earth Hour annually around the world since then. A study in 2014 claimed that the event (18) electricity consumption by an average of 4%. More importantly, it has helped raise (19) of climate change and has become a symbol of our commitment to protecting our planet. Although one hour can't change the world, it encourages governments and people to set long-term (20) for sustainable development around the world.

The event takes (13) annually around the world.