def extract_performance_data(data):
    """
    Extracts and returns relevant performance data from input list of tuples.

    Args:
        data (list): List of tuples containing v5_id, score, time, and memory usage.

    Returns:
        tuple: Tuple containing the v5_id with the highest score and its corresponding score.
    """
    best_v5 = max(data, key=lambda x: x[1])
    return best_v5[:2]

# Example usage
data = [('v5_1768236144', 108217.11959687909, 721, 15009.3),
        ('v5_1768235312', 89435.63603047856, 734, 12184.7),
        ('v5_1768235983', 98379.19963352643, 987, 9967.5)]

print(extract_performance_data(data))