endocrinology Q1

A 65-year-old female is admitted with an intracranial bleed under the care of the neurosurgeons. Following Magnetic resonance angiography she undergoes clipping of an cerebral arterial aneurysm and was well the following morning.
The surgical team document the following blood chemistry results on successive postoperative days:
Day 1:Plasma Sodium 130 mmol/L, Potassium 3.5 mmol/L, Urea 4.2 mmol/L, Creatinine 95 µmol/L
Day 2:Plasma Sodium 127 mmol/L, Potassium 3.4 mmol/L, Urea 4.2 mmol/L, Creatinine 90 µmol/L
Day 3:Plasma Sodium 124 mmol/L, Potassium 3.4 mmol/L, Urea 4.4 mmol/L, Creatinine 76 µmol/L
Day 4:Plasma sodium 120 mmol/L, Potassium 3.5 mmol/L, Urea 5 mmol/L, Creatinine 70 µmol/L
Normal Range:Plasma sodium 137-144 mmol/L, Potassium 3.5-4.9 mmol/L, Urea 2.5-7.5 mmol/L, Creatinine 60-110 µmol/L
On day 4 she was commenced on a fluid restriction of 1 litre per day. Investigations at that time show:
Plasma osmolality:262 mOsmol/L (278-305)
Urine osmolality:700 mOsmol/L (350-1000)
Urine sodium:70 mmol/L

Select the most likely diagnosis to explain these findings?
1-Cranial diabetes insipidus
2-Hypoadrenalism
3-Fluid overload
4-Syndrome of inappropriate ADH (SIADH)
5-Sick cell syndrome