Task: Identify the primary emotion conveyed in the tweet and assign it to either 'neutral or no emotion' or one or more of the provided emotions (anger, anticipation, disgust, fear, joy, love, optimism, pessimism, sadness, surprise, trust) that best capture the tweeter's mental state.
Tweet: Harking back to 2012 - DT's challenge to @POTUS...I will give...DT a hearty thank you...if he will release his tax returns....
This tweet contains emotions: 
joy