The greatest flaw in columbus' plan to reach asia by sailing west that
a. he greatly underestimated the circumference of the earth and did not know about the existence of the continents of north and south america
b. he did not possess the necessary technology to successfully make such a long voyage and return home safely
c. he could get the better-equipped and better-trained portuguese mariners to sign on to his plan and him achieve a successful voyage
d. genoa was too far from portugal and the differences in language and customs was too great for the two peoples to work together