Select the option that correctly fills the blanks in the following statements.
A. Glucose has `ul((i))` carbon atoms, pyruvic acid has `ul((ii))` carbon atoms and the acetyl group has `ul((iii))`carbon atoms.
B. Electrons enter the electron transport system as parts of hydrogen atoms attached to `ul((i))` and `ul((ii))`.

Options

A. `{:(" "A," "B),((i)-6(ii)-4(iii)-3,(i)-NADH(ii)-FADH_(2)):}`
B. `{:(" "A," "B),((i)-6(ii)-3(iii)-2,(i)-NADH(ii)-FADH_(2)):}`
C. `{:(" "A," "B),((i)-6(ii)-3(iii)-2,(i)-ATP (ii)-GTP):}`
D. `{:(" "A," "B),((i)-6(ii)-4(iii)-3,(i)-ATP(ii)-GTP):}`

Answer

To solve the question, we need to fill in the blanks with the correct number of carbon atoms for each compound mentioned in the statements.

### Step-by-Step Solution:

**A.**
1. **Glucose:**
- Glucose is a simple sugar and is known to have **6 carbon atoms**. This is a fundamental fact in biology, as glucose is often represented as C6H12O6.
- Therefore, for blank (i), we write **6**.

2. **Pyruvic Acid:**
- Pyruvic acid is the end product of glycolysis and is known to have **3 carbon atoms**. It is represented as C3H4O3.
- Thus, for blank (ii), we write **3**.

3. **Acetyl Group:**
- The acetyl group, which is part of acetyl coenzyme A, is derived from pyruvic acid when it loses a carbon dioxide molecule. The acetyl group has **2 carbon atoms**.
- Hence, for blank (iii), we write **2**.

So, the completed statement for part A is:
- Glucose has **6** carbon atoms, pyruvic acid has **3** carbon atoms, and the acetyl group has **2** carbon atoms.

**B.**
1. **Electrons in the Electron Transport System:**
- Electrons enter the electron transport system as part of hydrogen atoms that are attached to **NADH** and **FADH2**. These are the reduced forms of NAD+ and FAD, which are generated during the Krebs cycle.
- Therefore, for blank (i), we write **NADH**, and for blank (ii), we write **FADH2**.

So, the completed statement for part B is:
- Electrons enter the electron transport system as parts of hydrogen atoms attached to **NADH** and **FADH2**.

### Final Answers:
- A. (i) 6, (ii) 3, (iii) 2
- B. (i) NADH, (ii) FADH2