B1
because of
Dictionary examples:
Due to a banana peel, the clown's grand entrance became a hilarious slip-and-slide show. (0.0)
Due to a misunderstanding, the chef put candles on the birthday steak. (0.0)
Due to a typo, the wedding invitation said 'Bring your own bride.' (0.0)
Due to wet leaves on the line, this train will arrive an hour late. (56.2)
A lot of her unhappiness is due to boredom. (64.8)