Final answer:
The Main View subtab in the Intraday tab is the correct option for viewing a portfolio's performance using real-time data in portfolio management software.
Step-by-step explanation:
The correct option for viewing your portfolio's overall current performance using real-time data is c. The Main View subtab in the Intraday tab. This feature is typically found in portfolio management software, under the Intraday tab, where real-time performance tracking allows investors to monitor their positions as market conditions change throughout the trading day. Options a, b, and d, including the Period Analysis, Statistical Summary, and Seasonal Analysis subtabs, usually focus on historical data or other types of performance analyses that do not necessarily provide real-time portfolio updates.