1 (a) That's right. The harm that B has suffered in these circumstances consists of lost earnings and appears to be purely economic (or financial). B is not physically injured in any way as a result of A's negligent misstatement. (Although being told the wrong results caused a loss of confidence, the facts do not disclose any psychiatric harm.)
Purely economic harm is recognised as sufficient for the purposes of Negligence, whether caused by a physical act or (as in this case) by a negligent misstatement. In relation to the job from which she was dismissed, the loss is an actual loss and, provided the other elements of liability are satisfied, B could claim damages to compensate for this loss.