Let's see your options:
a) prominences are gas eruptions that can form an arch and do not look dark, therefore this statement is false;
b) solar flares are spots hotter than the surrounding, therefore they are brighter than the rest, and they form where prominences start or end on the surface, therefore this statement is true;
c) the number of sunspots may vary following an 11 years cycle, therefore this statement is false;
d) sunspots are colder spots on the surface and have nothing to do with solar winds, therefore this statement is false.