Step 1: Read the stem as asking which option is a false blanket statement. The absolute word "must" in option c is the clue.
Step 2: Clinically, treatment of a haematoma is individualised. A small subcutaneous bruise resolves on its own with conservative care, whereas a large or expanding collection in a tight space may need drainage. Surgery is therefore conditional, not universal.
Step 3: Because not every haematoma requires an operation, the categorical statement "haematoma must be operated" cannot be correct.
Step 4: Verifying the remaining choices: imaging is appropriately used to evaluate a haemorrhage, and the GCS is a standard prognostic index, especially in traumatic brain injury. Both are true, so the odd one out is the surgical-mandate statement.
\[\boxed{\text{Haematoma must be operated}}\]