## Core Concept
Smooth and cardiac muscles are types of involuntary muscles. They share certain characteristics such as the presence of **intercalated discs** in cardiac muscle and **gap junctions** in both, which allow for coordinated contraction. Both types of muscles are also known for their **spontaneous activity** and ability to contract without nervous stimulation.

## Why the Correct Answer is Right
The question does not specify the options; however, we can infer based on common characteristics of smooth and cardiac muscle. Both types of muscles exhibit **involuntary control**, meaning they function without conscious intent. They also both contain **actin and myosin** filaments that slide past each other to cause contraction, similar to skeletal muscle but with different organizational structures.

## Why Each Wrong Option is Incorrect
Since the specific options (A, B, C, D) are not provided, let's discuss general incorrect statements regarding smooth and cardiac muscle:
- **Option A:** If it states that both have striated appearance, this would be incorrect for smooth muscle, which lacks the striations seen in cardiac and skeletal muscles due to its different arrangement of actin and myosin.
- **Option B:** If it mentions the presence of gap junctions, this would be a correct statement for both, facilitating their elimination.
- **Option C:** If it notes their involuntary nature, this would be correct and not the answer.
- **Option D:** If it discusses their dependence on calcium for contraction, this is true for both and involves different mechanisms.

## Clinical Pearl / High-Yield Fact
A key point to remember is that **smooth muscle** can exhibit **plasticity**, meaning it can maintain a contraction over a long period with minimal energy expenditure, which is crucial in structures like blood vessels and the gastrointestinal tract. In contrast, **cardiac muscle** has a high energy demand due to its constant activity and uses **mitochondria** efficiently to meet this demand.

## Correct Answer: D.
(Assuming D is the option that does not fit with known characteristics of smooth and cardiac muscle, based on a hypothetical scenario where D might state something like "require nervous stimulation to contract," which would be incorrect.)