Which is true of diagnosing and troubleshooting?
diagnosing attempts to identify the source of a problem, while troubleshooting looks for the nature of the problem.
diagnosing is used to fix problems with hardware, while troubleshooting is used to fix problems in program code.
diagnosing looks for the nature of the problem, while troubleshooting attempts to identify the source of the problem.
diagnosing is used to fix problems in program code, while troubleshooting is used to fix problems with hardware.

Diagnosing looks for the nature of the problem, while troubleshooting attempts to identify the source of the problem.

Explanation:

Diagnosing is the first part of a problem investigation/resolution. It attempts to replicate the problem and identify the global source of the problem.  For example, if your computer won't turn on, a diagnostic would make examine if the computer is connected and if there's power in the outlet.  If so, the diagnosis will conclude there's an issue with the power system of the computer.

Then the troubleshooting comes into play. Ok, we know the problem is about the power system of the computer since electricity is provided.  Now, is the problem with the cable?  The power supply? A faulty connector? Maybe it's just the power button that is broken?  and so on. It's a detailed procedure to find the specific source of the problem (and fix it).

Diagnosing attempts to identify the source of a problem, while troubleshooting looks for the nature of the problem.

Explanation:

Diagnosing is about figuring out what the problem is, while troubleshooting is about solving the problem.

Therefore when you perform a diagnosis of your PC, you are trying to identify the source of the problem. Once the diagnosis is complete, troubleshooting will try to fix the problem by looking at the nature of the problem and how it can be fixed.  

For example, the diagnosis identifies the problem: you need to update a specific controller. Troubleshooting will then look for updates on the internet and download them. Problem solved.

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