ATP is

Options

A. Adenosine D-ribose triphosphate
B. Adenosine L-ribose triphophate
C. Adenine D-ribose triphophate
D. Adenine L-ribose triphosphate.

Answer

### Step-by-Step Solution:

1. **Understanding the Structure of ATP**:
- ATP stands for adenosine triphosphate. It is a nucleotide that serves as the primary energy carrier in cells.
- A nucleotide consists of three components: a nitrogenous base, a pentose sugar, and one or more phosphate groups.

2. **Identifying the Components of ATP**:
- The nitrogenous base in ATP is adenine.
- The sugar component is ribose, which is a five-carbon sugar.
- ATP contains three phosphate groups attached to the ribose sugar.

3. **Recognizing the Nomenclature**:
- The term "adenosine" refers to the combination of adenine and ribose.
- When adenine is combined with ribose, it forms adenosine.
- When adenosine is combined with three phosphate groups, it becomes adenosine triphosphate (ATP).

4. **Evaluating the Options**:
- The options provided are:
1. Adenosine D-ribose triphosphate
2. Adenosine L-ribose triphosphate
3. Adenosine D-ribose triphosphate
4. Adenine L-ribose triphosphate
- The correct form of ribose in ATP is D-ribose, as most sugars in biological systems are in the D-form.

5. **Selecting the Correct Answer**:
- Since ATP is composed of adenine, D-ribose, and triphosphate, the correct answer is:
- **Option 3: Adenosine D-ribose triphosphate**.