**Core Concept**
The Indian Penal Code (IPC) is a comprehensive code that defines various offenses and their punishments. Section 319 of the IPC defines "hurt," while Section 320 defines "grievous hurt," which is a more severe form of physical injury.

**Why the Correct Answer is Right**
Grievous hurt is a serious physical injury that can have long-term consequences for the victim. According to the IPC, Section 320 defines grievous hurt as any of the following: permanent privation of the sight of either eye, permanent privation of the hearing of either ear, privation of any member or joint, destruction or permanent impairing of the powers of any member or joint, permanent disfiguration of the head or face, fracture or dislocation of a bone or tooth, any hurt which endangers life or which causes the sufferer to be during the space of twenty days in severe bodily pain, or unable to follow his ordinary pursuits.

**Why Each Wrong Option is Incorrect**
**Option A:** Defines hurt - This is incorrect because Section 319 of the IPC defines hurt, not 320. Hurt is a broader term that encompasses any physical injury, whereas grievous hurt is a more severe form of injury.

**Option B:** Defines murder - This is incorrect because murder is defined in Section 299 of the IPC, not Section 320. Murder is the unlawful killing of a human being with intent or knowledge that the act would cause death.

**Option C:** Attempt to murder - This is incorrect because attempt to murder is defined in Section 307 of the IPC, not Section 320. Attempt to murder is an attempt to cause death with the intention of causing death.

**Clinical Pearl / High-Yield Fact**
To remember the difference between hurt and grievous hurt, recall that hurt is a broader term that encompasses any physical injury, whereas grievous hurt is a more severe form of injury that can have long-term consequences for the victim.

**✓ Correct Answer: D. Defines grievous hurt**