patient who has been admitted following a myocardial infarction has developed a broad complex tachycardia. diagnosis of ventricular tachycardia.. Hypomagnesaemia

You are called to the coronary care unit. A patient who has been admitted following a myocardial infarction has developed a broad complex tachycardia. You suspect a diagnosis of ventricular tachycardia. Which one of the following factors may have precipitated this?
A.A Hypoglycaemia
B.A Bisoprolol
C.A Hypomagnesaemia***
D.A Dehydration
E.A Hyperkalaemia.