Computer Science

A binary number system uses only two digits: 0 and 1. The number 202 contains the digit 2, so it is not a valid binary number.

Evan Spiegel is the co-founder and CEO of Snapchat, a popular multimedia messaging app. The other options are well-known figures in computing and technology but are not associated with the founding of Snapchat.

Dynamic RAM (DRAM) stores data using capacitors that gradually lose charge, so it must be refreshed repeatedly every few milliseconds to retain information. In contrast, SRAM, ROM, and EPROM do not require constant refreshing. This makes DRAM slower but more cost-effective for main memory.

In older versions of Microsoft PowerPoint, the Common Tasks toolbar was a context-sensitive toolbar that provided different options depending on the active master view (Slide Master, Handout Master, or Notes Master). This toolbar allowed quick access to frequently used commands relevant to the master view being edited. Other toolbars like Drawing, Formatting, and Standard toolbars are more general-purpose and do not change their options based on the master view. Although the Common Tasks toolbar is not present in recent versions of PowerPoint, the question and answer correctly refer to its function in earlier versions.

The shortcut 'Alt + F4' is the standard key combination used to close the active program window in most operating systems, making option B correct.

Modem, ISDN, and DSL are technologies used to provide internet or web access connectivity. UDP (User Datagram Protocol) is a transport layer communication protocol used for data transmission over networks, not a method or technology for accessing the web.

MS-DOS is a single-user, single-tasking operating system, meaning it allows only one user to perform one task at a time. Windows and Mac OS are modern operating systems that support multi-user and multitasking capabilities.

Content-Addressable Memory (CAM) is designed for very high-speed searching because it allows data to be retrieved based on content rather than specific addresses. This makes it much faster for search-intensive applications compared to traditional memory types like RAM or flash memory.

In Microsoft Excel, the shortcut Shift+F9 is used to calculate the active worksheet (current sheet) only, whereas F9 calculates all worksheets in all open workbooks. Therefore, option B is correct.

Pascal is a high-level procedural programming language developed in the late 1960s. Lotus is a spreadsheet application, MS-Excel is a spreadsheet software, and Netscape is a web browser, none of which are programming languages.