Answer:
Giggles
Step-by-step explanation:
Wail can be defined as to: "give a cry of pain, grief, or anger."
Shriek can be defined as a: "utter a high-pitched piercing sound or words, especially as an expression of terror, pain, or excitement."
Growl can be defined as: "of an animal, especially a dog) make a low guttural sound in the throat."
None of these pass a very good connotation, so we can surely discard all of them and use Giggles, which is: "a light, silly laugh."