which one is the simple sentence?

The question is asking which of the given options is a "simple sentence". A simple sentence is a sentence that contains only one independent clause and expresses a complete thought. Out of the options given, only 'I know the place of his living' is a simple sentence because it contains only one independent clause "I know" and expresses a complete thought. The other options contain dependent clauses and additional phrases that make them compound or complex sentences. Therefore, the correct answer is 'I know the place of his living'.