Match the texts with their titles. There is one extra title.

{"A"=>{"title"=>"4. COLD MOUNTAINS", "explanation"=>"Text A describes how air temperature decreases with altitude, explaining why mountain tops are cold."}, "B"=>{"title"=>"5. LARGER THAN PASSENGER LINERS", "explanation"=>"Text B discusses submarines that are larger than passenger liners and their capabilities."}, "C"=>{"title"=>"2. HIGH LIVING", "explanation"=>"Text C talks about people and animals living at high altitudes and how they adapt to the low oxygen environment."}, "D"=>{"title"=>"1. SPACE CITIES", "explanation"=>"Text D discusses future space travel and living in space cities."}, "E"=>{"title"=>"3. GIANT SHIPS", "explanation"=>"Text E describes large oil tankers, the largest ships ever built."}, "F"=>{"title"=>"6. GRAVITY IN SPACE", "explanation"=>"Text F describes building giant colonies in space, and how that would affect gravity."}, "extra_title"=>"7. GIANT PLANES", "extra_title_explanation"=>"There is no text that describes giant planes, thus this is an extra title that should not be matched."}