Choose the correct sentence (advanced conjunction):

Fire : Hot :: Ice : ?

Choose the correct sentence (advanced grammar):

Read the passage: \'Renewable energy sources like solar and wind now account for 30% of global electricity. However, their intermittency requires advanced battery storage systems to ensure consistent supply.\' What is the main challenge mentioned?

\'You should study hard,\' she said. (Indirect speech)

The ball is in your court means: