Help with selection of stock exchange for a gold stock

[landlord]

I am trying to buy shares in this Royalty company "sandstorm gold" SAND.
When I type the name into Yahoo Finance I get the following choices.....

AYS1.F-STANDSTORM GOLD
Equity-Frankfurt

SAND-STANDSTORM GOLD LTD
Equity-NYSE-MKT

SSL.TO-STANDSTORM GOLD LTD
Equity-Toronto

AYS1.SG-STANDSTORM GOLD
Equity-Stutgart

SDXXF-STANDSTORM GOLD LTD
Equity-OTC Markets

SNXZF-STANDSTORM GOLD
Equity-OTC Markets

AYS1.BE-STANDSTORM GOLD
Equity-Berlin

I would love to purchase the stock on one of the German stock exchanges in euro to save on currency conversion costs, but the ticker codes quoted here weren't recognised by my Degiro stockbroking account.
Any advantage in purchasing this stock on the New York or Toronto stock exchange ? Could liquidity be an issue?
What is the OTC market ?