Answer:
Elliott raised his grades from failing to mostly A-grades.
Explanation:
The question is about Elliot's recovery. It could be a recovery from an ailment, depression or from a particular state of mind. Recovery in this sense is physiological or psychological. It has nothing to do with academics. Therefore we can conclude that the option which had the least impact on Elliot's recovery is : "Elliott raised his grades from failing to mostly A-grades."