What do you call beach protective structures like the one in the picture?

[![enter image description here][1]][1]

I found a number of possible words but not sure which is most appropriate:  
 **pier, jetty, wharf, quay, staith, groyne/groin, breakwater, seawall**   
 (all credit to [Wikipedia][2]).

Update: The main function is to protect the beach sand from being removed by the waves. Also it is a nice wave and currents protection for swimmers. Often people jump from it in the water. Or just go to it as an observation point. Not on this one but on others, small boats sometimes dock. On one of them wake-surfing construction is installed. For the record this is in the city of Varna on the Black sea coast. July and August is the best time.

  [1]: https://i.sstatic.net/yzaKn.jpg
  [2]: https://en.wikipedia.org/wiki/Seawall