A. Option 4 Late pregnancy. The relative increase in plasma volume in late pregnancy results in a low haematocrit.
B. Option 1 Fainting. The vagal element of the vaso-vagal faint can cause severe bradycardia.
C. Option 5 Hypothermia. The decrease in the metabolic rate in hypothermia reduces oxygen consumption.
D. Option 2 Severe haemorrhage. The intense reflex venoconstriction in severe haemorrhage may make it difficult to insert catheters for introducing intravenous fluids.
E. Option 6 Lying down. Due to the increase in venous return to the heart.