The right combination of the two sentences is: Roberto's confidence threatened to crumble, <u>but</u> he took a deep breath and shook off his doubts as he thought about all the hours he'd practiced.
<h3>Meaning of Conjunctions</h3>
Conjunctions are words that are used to join sentences so that they make meaning. In the list of options, we have a number of conjunctions. The right conjunction to choose will be the one that shows contrast.
While Roberto's confidence was about to crumble, it was the deep breath and overcoming of doubts that helped him. The choice, "but" served that purpose.
Learn more about conjunctions here:
brainly.com/question/933741
