田中さんが ___ ___ _★_ ___ 知りませんか。

The correct sentence order is: '田中さんが 今(3) どこに(0) いる(2) か(1) 知りませんか。' (Do you know where Mr. Tanaka is now?). Grammatical breakdown: This is an embedded question (indirect question) pattern: '[Question Word] + Verb Plain Form + か + 知る/分かる'. Here, '今' (now) and 'どこに' (where) are followed by the plain verb 'いる' (is/exists) and the question particle 'か'. The third position (★) is filled by 'いる' (Choice 'いる').