6. in the rock, which mineral melts first (at the lowest temperature like the ice chips)? quartz potassium feldspar amphibole

In the rock, Quartz will melts first at the lowest temperature like the ice chips. Option A

Explanation:

Quartz would be the first mineral to melt in a rock if it is present in the rock as the rock is heated up. Whenever heat is provided to a rock, rock starts melting and the minerals which form the composition of that rock start melting but at different temperatures but the first mineral to melt in a rock would be quartz if present in the rock and the last one to melt would be olivine (if present in the rock).