Choose the correct answer A, B, C or D for each of the gaps complete the following text

This new home robot has three programmes: it can (1) ______ the house, it can clean the floor and it can interact (2) ______ people. Kitty 2012 is fast and intelligent. When we’re away, it can listen for certain noises and (3) ______ signals to our mobile phone if there’s trouble or danger. It can move (4) ______ the house and climb steps to find dirty places and clean them. It has cameras in its eyes so it can watch people and react to them.

(1) ___________

• A. 
  guard
• B. 
  wake
• C. 
  look
• D. 
  prevent