ahmed_btm posted:Yes, the only correct answer here is: 'had'. The backshift isn't needed here.
Hi, Rasha and Ahmed_btm,
I agree with Ahmed_btm that backshift isn't needed. However, it does not follow from the fact that backshift isn't needed that it isn't possible or correct.
It is perfectly correct to use backshift ("had had") in the indirect version of "I was told, 'Your friend had a terrible accident while he was driving to Mansoura.'"
Therefore there are two correct answers here: (a) and (b). Backshift does not also have to take place with "was driving," which is subordinate to "had had."