Question: If I am playing a Concealed Hand, do I also have to pick my own Mah Jongg tile?

Answer: The letter “C” to the right of the hand indicates one cannot call to expose tiles during the game.  However, when playing a concealed hand, there is an exception is: you can call a discarded tile that results in Mah Jongg.   

Source:  Mah Jongg Made Easy 2024 pg. 15