Which of the following phases of matter gives off light? A. Liquid B. Plasma
C. Gas
D. Solid

Spontaneity tell us the direction of the reaction, but not how fast it goes. gibbs free energy brings together enthalpy, entropy and temperature in one easy formula. g = h - ts. and, finally the sign of delta g is always negative for a spontaneous reaction.

B"hf and f-"  is the correct answer took the test on edgenuity and got it right