The Medici bank differed from other banks in one very important way, and the chance of a large borrower defaulting did not pose a significant risk. The Medici bank was:

a Diversified, and made up of interlocking relationships dependent on the rest

b Centralized, and made up of interlocking relationships, each dependent on the rest

c Centralized, and lent to people that were related

d Diversified, and made up of interlocking partnerships, each independent from the rest