Step 1: Understand the structure of hypophosphorous acid.
Hypophosphorous acid is a weak acid with the molecular formula H$_3$PO$_2$. It contains one phosphorus atom bonded to two hydroxyl groups (-OH) and one -OOH group (hydroperoxide group).
Step 2: Analyze each option.
- Option (A) is incorrect because it shows a double bond to oxygen, which is not the structure of hypophosphorous acid.
- Option (B) is incorrect because it shows two hydrogen atoms attached to phosphorus, which is not typical for this acid.
- Option (C) is the correct structure, showing the correct bonding with one hydroxyl group and one hydroperoxide group (-OOH).
- Option (D) is incorrect because it shows two hydroxyl groups and no hydroperoxide group.
Step 3: Apply to the options.
The correct structural formula for hypophosphorous acid is shown in option (C).
Final Answer:
\[
\boxed{\text{HO–P–OOH}}
\]
