Read the following statements and find out the incorrect statement

Options

A. Second step of Calvin cycle (i.e, reduction) involve utilisation of 2 molecules of ATP for reduction and 2 of NADPH for phosphorylation per `CO_(2 )` molecule fixed
B. The regeneration steps require one ATP for phosphorylation to fonn RuBP.
C. It is probably to meet the differences in number of ATP and NADPH used in dark reaction that the cyclic phosphorylation takes place.
D. Plants that are adapted to dry tropical regions have the `C_(4)` pathway

Explanation

To determine the incorrect statement among the given options regarding the Calvin cycle and photosynthesis, we will analyze each statement step by step.

### Step-by-Step Solution:

1. **Understanding the Calvin Cycle**: The Calvin cycle, also known as the C3 cycle, consists of three main steps: carboxylation, reduction, and regeneration. Each step has specific roles and requirements in terms of ATP and NADPH.

2. **Analyzing Option 1**:
- The statement claims that the second step of the Calvin cycle (reduction) involves the utilization of two molecules of ATP and two molecules of NADPH for the phosphorylation of carbon dioxide.
- In reality, the reduction phase of the Calvin cycle uses **six molecules of NADPH** and **six molecules of ATP** for the conversion of 3-phosphoglycerate to glyceraldehyde-3-phosphate (G3P).
- Therefore, this statement is **incorrect**.

3. **Analyzing Option 2**:
- This statement mentions that the regeneration step requires one ATP for phosphorylation to form ribulose bisphosphate (RuBP).
- This is correct as the regeneration phase does indeed require ATP to regenerate RuBP from G3P.
- Thus, this statement is **correct**.

4. **Analyzing Option 3**:
- The statement discusses cyclic phosphorylation occurring to balance the differences in the number of ATP and NADPH used in the dark reactions.
- This statement is also **correct** as cyclic phosphorylation helps in generating additional ATP to meet the energy demands of the Calvin cycle.

5. **Analyzing Option 4**:
- This statement claims that plants adapted to dry tropical regions utilize the C4 pathway, which minimizes photorespiration and optimizes the Calvin cycle.
- This is **correct** as C4 plants are indeed adapted to hot and dry environments, allowing for efficient carbon fixation.

### Conclusion:
After analyzing all the options, the **incorrect statement is Option 1**.