Contrasted against traditional banks and their keeping records of balances and transactions at a centralized location, in Bitcoin all transactions are stored digitally as "blocks" in a chain that is kept by a network of peers.
A. Contrasted against traditional banks and their keeping records of balances and transactions at a centralized location,
B. Contrasted with traditional banks and their keeping records of balances and transactions at a centralized location,
C. Since it is in contrast to traditional banks and their keeping records of balances and transactions at a centralized location,
D. Contrasted to records of balances and transactions kept at a centralized location by the traditional banks,
E. In contrast to traditional banks, which keep records of balances and transactions at a centralized location,
The sentence would like to compare Bitcoin with another entity. In this case, the logical comparison is to compare with Banks.
Option A - Contrasted against traditional banks and their keeping records of balances and transactions at a centralized location,
this option compares 'traditional banks' and 'keeping records' with Bitcoin, which is inconsistent (banks is a noun, bitcoin is a noun but keeping records is a noun phrase
compared against vs compared with -> seems okay
B. Contrasted with traditional banks and their keeping records of balances and transactions at a centralized location,
Same reason as A.
C. Since it is in contrast to traditional banks and their keeping records of balances and transactions at a centralized location,
Same reason as A
D. Contrasted to records of balances and transactions kept at a centralized location by the traditional banks,
Comparing 'records of balances' with 'bitcoin'
E. In contrast to traditional banks, which keep records of balances and transactions at a centralized location,
Correct - comparing traditional banks to bitcoin