Explanation:

John von Neumann (often misspelled as Van Neumann) is widely credited with developing the concept of the stored-program computer architecture in the 1940s. This architecture, known as the von Neumann architecture, describes a design where both program instructions and data are stored in the same memory unit, which is fundamental to almost all modern computers. Option (b) Charles Babbage designed the Analytical Engine in the 19th century, a pioneering mechanical computer, but his architecture was not the 'basic architecture' for modern electronic computers in the same way von Neumann's was. Option (c) Blaise Pascal invented an early mechanical calculator (Pascaline). Option (d) Jordan Murn is not a recognized figure in computer architecture. Therefore, John von Neumann ($ \text{a} $) is the correct answer for the basic architecture of modern computers.