Select the incorrect statement.

Options

A. The geometry of phosphorus in `H_(3)PO_(2),H_(3)PO_(3)` and `H_(3)PO_(34)` is tetrahedral
B. `H_(3)PO_(2),H_(3)PO_(3)` and `H_(3)PO_(4)` are tribasic acids
C. `NH_(3)ltPH_(3)gtAsH_(3)ltSbH_(3)`: increasing acidic character.
D. `CO_(2) lt SiO_(2) lt SnO_(2) lt PbO_(2):` increasing oxidising power.

Explanation

To solve the question "Select the incorrect statement," we will analyze each statement related to the compounds H3PO2, H3PO3, and H3PO4, as well as the properties of the nitrogen family and the carbon family oxides.

### Step-by-Step Solution:

1. **Analyze Statement A**:
- The statement claims that the geometry of phosphorus in H3PO2, H3PO3, and H3PO4 is tetrahedral.
- **Structure Analysis**:
- H3PO4 (Phosphoric acid): P is bonded to four groups (3 OH and 1 P=O), which gives it a tetrahedral geometry.
- H3PO3 (Phosphorous acid): P is bonded to three groups (2 OH and 1 P=O), which also results in a tetrahedral geometry.
- H3PO2 (Hypophosphorous acid): P is bonded to three groups (1 OH and 2 H), maintaining tetrahedral geometry.
- **Conclusion**: Statement A is correct.

2. **Analyze Statement B**:
- The statement claims that H3PO2, H3PO3, and H3PO4 are tribasic acids.
- **Acidic Hydrogen Analysis**:
- H3PO4 has 3 acidic hydrogens (tribasic).
- H3PO3 has 2 acidic hydrogens (dibasic).
- H3PO2 has 1 acidic hydrogen (monobasic).
- **Conclusion**: Statement B is incorrect.

3. **Analyze Statement C**:
- The statement discusses the order of increasing acidic strength of the hydrides in the nitrogen family.
- **Basicity Trend**:
- In the nitrogen family, basicity decreases down the group (NH3 > PH3 > AsH3 > SbH3 > BiH3).
- This implies that acidity increases down the group, which contradicts the statement.
- **Conclusion**: Statement C is incorrect.

4. **Analyze Statement D**:
- The statement claims that the oxidizing power of the oxides of the carbon family increases down the group.
- **Oxidizing Power Analysis**:
- As we move down the group, the stability of the +4 oxidation state decreases due to the inner pair effect, leading to an increase in oxidizing power.
- **Conclusion**: Statement D is correct.

### Final Answer:
The incorrect statements are **B** and **C**.