this article only says about the distance between earth and moon.If the moon is closer to earth there will be more solar eclipse.If the moon is farther from the earth there would be less solar eclipse.The size of the earth also matters.lets assume the earth is smaller than moon, than there will ofcourse be total solar eclipse
on the other hand if we assume that the sun is smaller then the moon, than there may be the possibility of total solar eclipse.
But I reached at a conclusion that the distance of moon frm earth is more important.

and both the answers a and d may be correct.

rgds