**Core Concept**
The human body is susceptible to injury from explosive blasts due to the rapid pressure changes caused by the shockwave. The effects of a blast wave on the body depend on the proximity to the explosion, the intensity of the blast, and the individual's anatomy.

**Why the Correct Answer is Right**
The primary organs injured in a blast are the ear and lung due to their anatomical characteristics and functional roles. The ear is particularly susceptible to noise-induced damage, and the blast wave can generate sound pressures exceeding 140 decibels, causing damage to the tympanic membrane and the auditory nerve. Similarly, the lungs are vulnerable to the rapid pressure change, leading to barotrauma, which can cause pneumothorax, pulmonary contusion, or even lung rupture. The blast wave can also cause the air in the lungs to expand rapidly, leading to alveolar rupture and hemorrhage.

**Why Each Wrong Option is Incorrect**
**Option B:** The kidney and spleen are more susceptible to blunt trauma injury from the primary fragmentation and secondary effects of the blast, such as flying debris. While they can be injured in a blast, they are not the first organs to be injured.
**Option C:** The pancreas and duodenum are not typically the first organs injured in a blast. The primary effects of the blast wave are more likely to affect organs with gas-filled spaces or those with a direct path for the shockwave to travel, such as the ear and lungs.
**Option D:** The liver and muscle are not typically the first organs injured in a blast. While the liver can be injured from blunt trauma, the muscle is not a primary target for blast-induced injury.

**Clinical Pearl / High-Yield Fact**
The blast injury pattern can be remembered by the acronym "BAROTRAUMA," which stands for Barotrauma, Air embolism, Respiratory failure, Ocular damage, Traumatic brain injury, Ruptured eardrums, and Abdominal injuries.

**✓ Correct Answer: A. Ear, lung**