Which of the following accurately compares the Han and Roman empires
a) Reliance on the labor of enslaved people weakened both empires because of repeated rebellions
b) Both empires ultimately succumbed to civil wars and fell from within, without outside intervention
c) Both empires successfully defended themselves against naval invasions but ultimately succumbed to foreign powers with larger armies
d) Faiths filtering in from the periphery eclipsed the secular and classical traditions on which both empires were founded