A, B, and C. The <cftransaction> tag has an isolation attribute. Whether the database respects this ISOLATION tag is beyond your control. Isolation levels can affect performance, with serializable the worst performer and READ UNCOMMITTED the best. Isolation levels also affect the way records are locked. D is the only answer that is false, because the database has full control over what is locked.
A2:
C. Answer A is incorrect because <cftransaction> supports rollbacks as well as commits. B is incorrect because a dirty read is possible, depending on the isolation level. D is also incorrect because <CFLOCK> has nothing to do with a database transaction per se.
A3:
B. If the inner <cftransaction> tag were terminated, the code would work.
