In (B), the first sentence is declarative and provides an answer to the first question in (A). The second sentence emphasises that Kate does indeed love "Mark", and not whomever else we might have assumed her to love. However, a sentence this verbose is unlikely to occur in everyday speech (or even in written language), be it in English or in German. Instead, one would most likely answer the echo question in (A) simply by restating: "Mark!". This is the same for both languages.