The segment of `DNA` which acts as the instrumental manual for the synthesis of the protein is:

Options

A. nucleotide
B. ribose
C. gene
D. nucleoside

Explanation

To answer the question regarding the segment of DNA that acts as an instrumental manual for the synthesis of proteins, we can follow these steps:

### Step 1: Understand the Options
The question provides four options: nucleotide, ribose, gene, and nucleoside. We need to determine which of these is directly involved in the synthesis of proteins.

### Step 2: Define Each Term
- **Nucleotide**: The basic building block of DNA and RNA, consisting of a sugar, a phosphate group, and a nitrogenous base.
- **Ribose**: A sugar molecule that is a component of RNA, not DNA.
- **Gene**: A segment of DNA that contains the instructions for synthesizing proteins.
- **Nucleoside**: A compound formed by a nitrogenous base attached to a sugar, without the phosphate group.

### Step 3: Identify the Correct Answer
Among the options, the term that specifically refers to a segment of DNA that provides the instructions for protein synthesis is **gene**. Genes are composed of hundreds to thousands of base pairs and encode the information necessary to produce proteins, which are made up of amino acids.

### Step 4: Conclusion
Thus, the correct answer to the question is **gene**.

### Final Answer
The segment of DNA which acts as the instrumental manual for the synthesis of the protein is **gene**.

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