A data scientist is preparing a dataset to train a text-to-text model for a question-answering task. One of the data points is the question 'What is the chemical symbol for gold?' and its corresponding answer 'Au'. Construct the complete, single-line training sample for this data point, following the specific format required by the model. Your answer should include the standard prefix for this task, the question, the separator, the start-of-sequence token, and the answer.