This one has me stumped. Three different marks the first one is a B on top of a crown. The 2nd says CAIRTE. The third one is 925. Something? I tried Google search. 925.com have not found anything.
Maybe after the 925 . it coulld be stylized version of Greek letters the first letter makes me think of Omega. The other mark says CLARTE if you google it you will find it.
Funny story about Sterling. I had a friend who ran the local town dump and on Sundays he had a yard sale in front of his house selling lots of things others threw away. Nothing wrong with that because he also had a table at the dump where people could put things that were still good and were free for the taking. So one Sunday I stopped at his yard sale and he had a couple of large buckets of Silverplate utensils. My wife liked to make windchimes out of old Silverware so I asked him the price. He said "25 cents each but don't expect to find any Sterling in there, I've been over every piece to make sure none slipped through". Fair enough we just want some nice matching pieces to make wind chimes. Among the things we bought were 12 butter knives with ornate handles. When sorting through the stuff at home I realized that hidden in the design was a marking I had never seen before so I Googled it. French Sterling and that particular stamping indicated .950 Sterling. Thanks buddy... lol
The "B on top of a crown" mark is actually a "B on top of an M styled as a crown". It's the mark used by the Benaki Museum shop in Athens, Greece.
They sell high quality replicas of mainly Byzantine antiquities held by the museum in both silver and silver plate, branded "CLARTE". Yours is .925 silver and probably relatively recent (no more than tens of years old).