Evaluate the strategies and innovations that contributed to Duolingo's growth. Select all correct statementsEvaluate the strategies and innovations that contributed to Duolingo's growth. Select all correct statementsCommitted to a free core service, aligning with their mission to democratize language learning. Introduced a subscription model for an ad-free experience in response to user feedback. Incorporated gamification to increase user engagement and differentiate from competitors. Founders used their backgrounds to address global language learning needs. Launched their app at a time coinciding with the rise of mobile applications, aiding in user acquisition. Initially utilized a crowd-sourced translation model for revenue, later discontinued