Please explain why (a) is answer. Thank you

For the reaction YX at standard conditions with [Y]=1M and [X]=1M,G is initially a large negative number. As the reaction proceeds, [Y] decreases and [X] increases until the system reaches equilibrium. How do the values of G and G change as the reaction equilibrates? (a) G becomes less negative and G stays the same. (b) G becomes positive and G becomes positive. (c) G stays the same and G becomes less negative. (d) G reaches zero and G becomes more negative