An audit of a banking transactions system has found that on an earlier…

An audit of a banking transactions system has found that on an earlier occasion, two joint holders of account 𝐴 attempted simultaneous transfers of Rs. 10000 each from account 𝐴 to account 𝐵. Both transactions read the same value, Rs. 11000, as the initial balance in 𝐴 and were allowed to go through. 𝐵 was credited Rs. 10000 twice. 𝐴 was debited only once and ended up with a balance of Rs. 1000.

Which of the following properties is/are certain to have been violated by the system?