Which of the following most accurately assesses the long-term implications of Ivan IV's time as ruler of the Russian Empire?
a) His struggles with boyars led them to continue to decline in power and status in the years after his rule
b) The role of the tsar did not continue past Ivan IV's rule, making the title largely ineffective
c) The Russian Orthodox Christian Church separated from the tsar and was no longer an important institution
d) The gentry became increasingly hostile to the tsar, making the tsar's struggles to power worse