Please Help Identify Hallmark On Forks

[cakollektor]

I purchased a set of 4 forks at an estate sale & haven't been able to identify their marks. The forks measure about 6-7/8" long & about 7/8" across the widest point. Each one is marked with three identical symbols on the back of the handle. Can anyone help? Thanks, Denise
All 4 forks look like the one pictured below.

These are photos of the marks on each fork.
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