Answer :
C. will be trading
If you had She or He at the beginning, It will say 'She/He will be trading' so saying that means that it 'will' happen in the future
If you had She or He at the beginning, It will say 'She/He will be trading' so saying that means that it 'will' happen in the future
Your answer is C. It is formed by auxiliary for the future tense 'will', the auxiliary verb 'be' + the action verb to which '-ing' is added to mark the progressive.