Select the synonym of
obstreperous

Let's check the definitions of the terms provided:
obstreperous: noisy and difficult to control.

boisterous: noisy, energetic, and cheerful; rowdy. (Synonym)

bashful: reluctant to draw attention to oneself; shy.

reticent: not revealing one's thoughts or feelings readily.

taciturn: reserved or uncommunicative in speech; saying little.

Therefore, boisterous is the closest synonym.