What Is the Minimum Pressure and Temperature for Diamond Formation $\circ$

What is the minimum pressure and temperature for diamond formation?

A) 8kbar, 150 ^$\circ$ C
B) 800kbar, 15,000 ^$\circ$ C
C) 80 kbar, 15,000 ^$\circ$ C
D) 800kbar, 1,500 ^$\circ$ C
E) 80kbar, 1,500 ^$\circ$ C