Explanation:

Algorithms: An algorithm is a list of instructions or formulas for solving a problem, based on conducting a sequence of specified actions. 

The set of instructions can also be expressed independently of any programming language to solve a specific problem which is called an algorithm. 

• The algorithm consists of a set of explicit and unambiguous finite steps that, when carried out for a given set of initial conditions, produce the corresponding output and terminate in a finite time. 
• For Example, To understand the concept of an algorithm, let us consider a simple example of real-life problem-solving. To look for the meaning of a word from a dictionary, one wouldn’t go to the first word in the dictionary and search until the required word is found. An algorithm can be applied by taking advantage of the alphabetical order of words in a dictionary. 
• Purpose: To obtain a solution to a problem through the computer, usually we have to provide the computer program with input or data. The program then takes this input and manipulates it according to its instructions and eventually produces an output that represents the computer solution to the problem.

Hence, we conclude that an algorithm is a set by step execution of the programme intended to solve a specific problem.

Hence option (4) is the correct answer.