LAS VEGAS (AP) ― A 20-year-old cellist from Rhode Island won the Miss USA crown and will represent the United States in this year’s Miss Universe pageant after voicing support for transgender beauty queens.

Olivia Culpo topped a field of 51 contestants on Sunday to take the title at the Planet Hollywood Resort & Casino on the Las Vegas Strip. She strutted across the stage in a lilac bikini and a purple evening gown adorned with a sparkly belt.

In the dreaded final question round, Culpo was faced with the most difficult question of the night: “Would you feel it would be fair that a transgender woman wins the Miss USA title over a natural-born woman?’’ Culpo never stumbled as she embraced the Miss Universe Organization’s recent decision to admit transgender contestants. The question came from a pageant follower on Twitter, a first for the competition.

“I do think that that would be fair but I can understand that people would be a little apprehensive to take that road because there is a tradition of natural-born women, but today where there are so many surgeries and so many people out there who have a need to change for a happier life, I do accept that because I believe it’s a free country,’’ Culpo said.

Culpo said she was short and chubby as a girl, but blossomed after a growth spurt. She spent her summers at band camp after learning to play the cello in second grade. Her parents are also musicians, and her love for music saw her perform at Symphony Hall in Boston and Carnegie Hall in New York City.

Culpo is a 2010 graduate of St. Mary Academy Bay View, an all-girls Catholic school in Riverside, where she was a member of the National Honor Society. She is a sophomore at Boston University.

“Beauty is found in the way you treat others,’’ she told pageant officials.

Rounding out the top five contestants were first runner-up Nana Meriwether of Maryland, second runner-up Audrey Bolte of Ohio, third runner-up Jade Kelsall of Nevada and fourth runner-up Jasmyn Wilkins of Georgia. As Meriwether and Culpo held hands waiting for the winner to be announced, Culpo bit her lip and cringed with anticipation.