Final answer:
The correct transition word to connect the sentences about two accomplishments is 'Also', as it introduces an additional point and maintains the flow of the text.
Step-by-step explanation:
The best transition word to connect sentences about the team's accomplishments of completing the testing phase and starting the training program is C. Also. This transition word signifies that an additional accomplishment is being introduced, aligning with the context of mentioning multiple successes. Transitional words and phrases are crucial in writing as they show connections between ideas, ensuring flow and clarity. Using the word 'also' similarly to how Dunn signals a shift to another success in her writing, we create a relationship between the sentences that helps readers follow the progression of achievements.