**Explanation:**

To measure the length of a chain, we need to determine the distance between the two handles. The handles are the points where the chain can be connected or held. There are different ways to measure the length of a chain, but the correct option in this case is **B) outside of one handle to outside of the other handle**.

Here's a detailed explanation of why this option is correct:

**a) Centre of one handle to centre of the other handle:**
- This option measures the distance between the centers of the two handles. It does not take into consideration the width of the handles or the thickness of the chain. As a result, this measurement would not accurately represent the true length of the chain.

**b) Outside of one handle to outside of the other handle:**
- This option measures the distance between the outer edges of the two handles. It includes the width of the handles and any additional space required for the chain to be connected or held.
- By measuring from the outside of one handle to the outside of the other handle, we can accurately determine the length of the chain and account for any extra space needed for handling or connecting purposes.
- This measurement is commonly used in various applications where the chain length needs to be accurately determined, such as in construction, manufacturing, and transportation industries.

**c) Outside of one handle to inside of the other handle:**
- This option measures the distance between the outer edge of one handle to the inner edge of the other handle. It does not take into account the width of the handles or any additional space required for connecting or holding the chain. Consequently, this measurement would not provide an accurate representation of the chain length.

**d) Inside of one handle to inside of the other handle:**
- This option measures the distance between the inner edges of the two handles. It does not account for the width of the handles or any additional space required for handling or connecting the chain. Thus, this measurement would not accurately represent the length of the chain.

In conclusion, measuring the length of a chain from the outside of one handle to the outside of the other handle is the most accurate and appropriate method as it accounts for the width of the handles and any extra space required for connecting or holding the chain.