`S_(1)`: Cubic system have four possible type of unit cells
`S_(2) : H_(2)O` is diamagnetic substance and it is weakly attracted in magnetic fields
`S_(3)`: Graphite is a covalent solid with vanderwaal's forces as well

Options

A. FFT
B. FTF
C. TFF
D. FFF

Explanation

To determine the truth value of the three statements provided, we will analyze each statement step by step.

### Step 1: Analyze Statement S1
- **Statement S1**: "Cubic system has four possible types of unit cells."
- **Analysis**: The cubic crystal system actually has three types of unit cells:
1. Simple Cubic (SC)
2. Body-Centered Cubic (BCC)
3. Face-Centered Cubic (FCC)
- **Conclusion**: This statement is **False**.

### Step 2: Analyze Statement S2
- **Statement S2**: "H2O is a diamagnetic substance and it is weakly attracted in magnetic fields."
- **Analysis**: Water (H2O) is actually a **paramagnetic** substance due to the presence of unpaired electrons in its molecular structure. It is not diamagnetic, which would mean it is repelled by magnetic fields.
- **Conclusion**: This statement is **False**.

### Step 3: Analyze Statement S3
- **Statement S3**: "Graphite is a covalent solid with van der Waals forces as well."
- **Analysis**: Graphite is indeed a covalent solid, characterized by layers of carbon atoms bonded covalently in a hexagonal arrangement. Between these layers, there are weak van der Waals forces that allow the layers to slide over one another.
- **Conclusion**: This statement is **True**.

### Final Summary
- S1: False
- S2: False
- S3: True

Thus, the overall answer is **FFT** (False, False, True).

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