**Core Concept**
Fosphenytoin is a prodrug of phenytoin, an antiepileptic medication. It is used to treat and prevent seizures. The drug's pharmacokinetics and pharmacodynamics are similar to those of phenytoin.

**Why the Correct Answer is Right**
Fosphenytoin can be administered via intravenous (IV) and intramuscular (IM) routes. The IV route is preferred for acute management of seizures due to its rapid onset of action. Fosphenytoin is metabolized by the liver to form phenytoin, which then exerts its antiepileptic effects. The phenytoin produced acts by inhibiting voltage-gated sodium channels in the neuronal membrane, stabilizing the threshold against hyperexcitability caused by excessive stimuli.

**Why Each Wrong Option is Incorrect**
**Option A:** Oral administration of fosphenytoin is not recommended due to its poor bioavailability and variable absorption.
**Option B:** Subcutaneous injection of fosphenytoin is not a standard or recommended route of administration.
**Option C:** Rectal administration is not typically used for fosphenytoin.

**Clinical Pearl / High-Yield Fact**
Fosphenytoin is unique in that it is 20 times more soluble in water than phenytoin, allowing for faster administration and reducing the risk of extravasation.

**Correct Answer:** C. Intramuscular