What gave Sticky sudden confidence as he approached the Whisperer?

Sticky's sudden confidence as he approached the Whisperer stems from the support and camaraderie he found within his new friendships. Throughout their adventures, Sticky, along with his friends in the Mysterious Benedict Society, collaborated and relied on one another. This sense of belonging and the encouragement from his friends bolstered his self-esteem, allowing him to confront challenges he might have otherwise found daunting. Their bond showed him that he was not alone, making him feel more empowered to face the Whisperer.

The other choices do not capture the specific moment of growth Sticky experienced. While his prior experiences and training might be helpful, they do not directly contribute to the newfound confidence he gained from his friendships during that critical moment. Similarly, the desire to impress his friends might cause pressure, rather than instill genuine confidence, so it is the support from his friends that truly empowers him.