Sentence 1: Mark wasn't sure what to get for his girlfriend Sara on her birthday. 
 Sentence 3: They all said Sara likes panda bears 
 Sentence 4:  Mark booked a flight to China for Sara's birthday 
 Sentence 5:  Sara played with panda bear cubs in a Chinese zoo on her birthday! 
 Option 1: He decided to surprise her with a scavenger hunt. 
 Option 2: Mark asked Sara's friends for recommendations.