Final answer:
The stiffening of the entire body during a seizure is called the tonic phase (option a). This phase features powerful muscle contractions and can precede the clonic phase with convulsive movements.
Step-by-step explanation:
When a patient experiences a seizure in which their entire body stiffened, it is referred to as the tonic phase. This is characterized by muscle contraction and rigidity, which can last from a few seconds to several minutes. The body's muscles contract powerfully, which can lead to a sudden fall if the patient is standing.
Following the tonic phase, the seizure may move into the clonic phase, where muscles begin to contract and relax rapidly, leading to convulsive movements. Myoclonic phase refers to seizures where brief twitches in a muscle or group of muscles occur, and the atonic phase is associated with a loss of muscle tone, causing the person to suddenly collapse or drop their head.
Hence, the answer is option a.