Need to decide MMDB - whether Unisql, CosmsDB, MongoDB etc

Hi, We have a 3-tier application written in.net C#, sql stored procs. We have to add enhancements that will cater to the following requirements : In a museum application (it will run on Mobile Browsers), when a person is located at position x says, then the person will be able to view exhibits on his left and right as Images say 1,2,11,12, when he moves forward the exhibits on his left and right will change to 3,4,13,14 and so on. We need a Multimedia Database to achieve this, please provide suggestions for the same. We are currently looking at Unisql , CosmosDB but need more inputs , options before we finalize. Any suggestions, pointers are welcome.

 

Thanks, Susan Manoj Thankachan