In a shock to those
who still lived under the impression that investments are closely monitored, a financial security group recently discovered a loophole for enabling a scammer to gain access to transactions made by a leading investment bank so that this person will be aware of any major deals that a corporation had made before these deals are announced to the public
(A) who still lived under the impression that investments are closely monitored, a financial security group recently discovered a loophole
for enabling a scammer to gain access to transactions made by a leading investment bank so that this person will be aware of any major deals that a corporation had made
(B) who had still been living under the impression that investments are closely monitored, a financial security group recently discovered a loophole
for enabling a scammer to gain access to transactions made by a leading investment bank so that this person was aware of any major deals that a corporation might have made
(C) who still were living under the impression that investments are closely monitored, a financial security group recently discovered a
loophole enabling a scammer to gain access to transactions made by a leading investment bank so that this person will be aware of any major deals that a corporation had made
(D) still living under the impression that investments are closely monitored, a financial security group recently discovered a loophole that enables a scammer to gain access to transactions made by leading investment banks so that this person is aware of any major deals that a corporation might make
(E) still living under the impression that investments
had been closely monitored, a financial security group recently discovered a loophole that will enable a scammer to gain access to transactions made by leading investment banks so that this person was aware of any major deals that a corporation might make
I started ruled out E becasue of usage of "had been", then ruled out A and B for unidomatic "for enabling" and C because missing pronoun for loophole.