Phosphorus bronze is an alloy made from copper, tin, and phosphorus. It is known for its excellent mechanical properties and is widely used in various applications. Let's analyze each statement to see which ones are true.

a) Contains 0.2% phosphorus:
Phosphorus bronze is named so because it contains phosphorus as one of its main alloying elements. The phosphorus content in phosphorus bronze typically ranges from 0.1% to 0.35%. Therefore, the statement that phosphorus bronze contains 0.2% phosphorus is true.

b) Phosphorus increases tensile strength:
Phosphorus bronze is known for its high strength and hardness. The addition of phosphorus helps in solid solution strengthening, which improves the tensile strength of the alloy. Therefore, the statement that phosphorus increases tensile strength is true.

c) Use for worm wheels and bearings:
Phosphorus bronze has excellent wear resistance and self-lubricating properties. These characteristics make it an ideal choice for applications where sliding or rotating contact occurs, such as worm wheels and bearings. Therefore, the statement that phosphorus bronze is used for worm wheels and bearings is true.

d) All of the mentioned:
Based on the explanations provided above, it is clear that all of the mentioned statements are true. Phosphorus bronze does contain phosphorus, which increases its tensile strength. It is commonly used for worm wheels and bearings due to its excellent wear resistance and self-lubricating properties.

In conclusion, the correct answer is option 'D' - all of the mentioned statements are true. Phosphorus bronze is an alloy that contains phosphorus, which enhances its mechanical properties. It is commonly used for applications such as worm wheels and bearings due to its high strength, hardness, wear resistance, and self-lubricating properties.