Which of the following is a restriction on the cutting of wire leads?

The correct choice indicates that wire leads must be left intact. This requirement is rooted in the principle of maintaining the integrity of the connections and ensuring reliable performance of the assembly. When wire leads are left intact, they allow for a proper connection to be made without the risk of damaging the component or compromising the electrical continuity.

Cutting leads too short or inadequately can lead to issues such as weak connections, increased resistance, or even failure of the component to perform as intended. Furthermore, leaving leads intact provides flexibility for adjustments during assembly or repair, as assembly technicians might need to manipulate leads to fit them properly into a circuit or connection. This practice also helps to ensure that the mechanical strength of the joint is preserved, which is crucial for both function and durability.

In contrast, the other options present conditions that could compromise the quality and reliability of the electronic assembly. For instance, cutting leads to an exact length might not always be feasible or practical in real-world scenarios, while using any tool to cut leads could lead to uneven cuts or damage. Additionally, requiring a protective coating on leads does not directly relate to the necessity of maintaining their length or integrity during the assembly process, making the option to leave leads intact the most relevant guideline.