The correct Active/Passive form of the given sentence is:

☀ Why was the job left by you?

Explanation for other options:

☀ Why did the job left by you? This option is in the active voice and changes the word order, but it is not the correct passive form. The correct passive form should be "Why was the job left by you?"

☀ Why the job was left by you? This option is in the passive voice, but it is missing the auxiliary verb "was." The correct form should be "Why was the job left by you?"

☀ Why had the job been left by you? This option uses the past perfect tense ("had been left"), which suggests an action completed before a certain point in the past. The original sentence is in the simple past tense, so the correct form should be "Why was the job left by you?"