Which rock has the highest metamorphic grade? rock formed at 500? C and 8 kilobars of pressure rock formed at 1,200? C and 20 kilobars of pressure rock formed at 400? C and 12 kilobars of pressure rock formed at 700? C and 10 kilobars of pressure

The rock with the highest metamorphic grade would be the one that is formed at '1,200 °C' and '20 kilobars of pressure'.

Explanation:

When it comes to the metamorphic grade of rock, it is clear that higher the heat and pressure the rock is subjected to, higher would be its metamorphic grade. Rocks with a high metamorphic grade are comparatively easy to identify because such rocks exhibit foliated surface. Gneiss is a "metamorphic rock" with the "highest metamorphic grade".

The ansswer is C i took the test