You are presented with the quiz "What does magma form?" 

But you don't know the answer, so you turn to your teacher to ask for hints. He says that "vein deposits of gold and silver are formed by igneous intrusion" and "if magma solidifies within the crust, the rock is called an intrusive igneous rock". 

So, what's the best answer to the question?


 

    vein deposits of gold       