Answer : 1. "BASIC"
Explanation :

The language considered the "foundation stone" for teaching languages like FORTRAN, ALGOL, PASCAL, and many others is ALGOL (Algorithmic Language). ALGOL was a significant early programming language that influenced the design of subsequent programming languages, providing important concepts and structures used in the development of languages like FORTRAN, PASCAL, and C. While BASIC is also a widely used beginner-friendly programming language, ALGOL had a substantial impact on the development of programming language theory and design.