The origin of the term Algorithm is traced to Persian astronomer and mathematician, Abu Abdullah Muhammad ibn Musa Al-Khwarizmi (c. 850 AD) as the Latin translation of AlKhwarizmi was called Algorithmi. A programmer writes a program to instruct the computer to do certain tasks as desired. The computer then follows the steps written in the program code. Therefore, the programmer first prepares a roadmap of the program to be written, before actually writing the code. Without a roadmap, the programmer may not be able to clearly visualize the instructions to be written and may end up developing a program that may not work as expected. Such a roadmap is nothing but the algorithm which is the building block of a computer program. Hence, it is clear that we need to follow a sequence of steps to accomplish the task. Such a finite sequence of steps required to get the desired output is called an algorithm. It will lead to the desired result in a finite amount of time if followed correctly. The algorithm has a definite beginning and a definite end and consists of a finite number of steps. In mathematics and computer science, an algorithm is a finite sequence of well-defined, computer-implementable instructions, typically to solve a class of problems or to perform a computation or produce the desired output. Algorithms are always unambiguous and are used as specifications for performing calculations, data processing, automated reasoning, and other tasks. We can express an algorithm in many ways, including natural language, flow charts, pseudocode, and of course, actual programming languages. An algorithm expressed in a programming language is called a computer program. An algorithm is expressed in a graphical form known as a flowchart. For example, searching using a search engine, sending a message, finding a word in a document, booking a taxi through an app, performing online banking, playing computer games, all are based on algorithms. Thus, option 4 is the correct answer.