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

☀ Were these vegetables grown in your own garden?

Explanation for other options:

☀ Was this vegetables grown in your own garden? This option has incorrect subject-verb agreement. The correct form should be "Were these vegetables grown in your own garden?" The plural form of "vegetables" should use "were" instead of "was."

☀ Were these vegetables grow in his own garden? This option uses the wrong verb form. The correct passive form should be "Were these vegetables grown," not "grow."

☀ Were that vegetables grows in your own garden? This option has incorrect subject-verb agreement and uses the wrong verb form. The correct form should be "Were those vegetables grown," not "that vegetables grows." Additionally, the plural form "those vegetables" should be used instead of "that vegetables."