**Core Concept**
The membrane attack complex (MAC) is a crucial component of the complement system, a part of the innate immune response that helps eliminate pathogens from the body. The MAC is formed through the assembly of various complement components, ultimately leading to the formation of a pore in the pathogen's membrane, causing cell lysis and death.

**Why the Correct Answer is Right**
The correct answer is formed through the assembly of C5b, C6, C7, C8, and multiple molecules of C9. This process begins with the activation of the complement system, which results in the cleavage of C5 into C5a and C5b. C5b then combines with C6, followed by C7, C8, and multiple C9 molecules to form the MAC. The MAC inserts into the pathogen's membrane, creating a pore that disrupts the cell's osmotic balance, leading to cell lysis.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is not a correct component of the MAC. While C5 is a crucial component in the formation of the MAC, it is not the correct answer.
* **Option B:** This option is not accurate, as C6 is indeed a component of the MAC but is not the correct answer on its own.
* **Option D:** This option is not correct, as C8 is a component of the MAC but is not the correct answer on its own.

**Clinical Pearl / High-Yield Fact**
The MAC is an essential component of the complement system, and its dysregulation can lead to various diseases, including paroxysmal nocturnal hemoglobinuria (PNH) and atypical hemolytic uremic syndrome (aHUS).

**Correct Answer:** C5b-9.