scope.js

const a = 1; const b = 2; const c = 3;
(function firstFunction () {
  const b = 5; const c = 6;
  (function secondFunction () {
    const b = 8;

    console.log(`a: ${a}, b: ${b}, c: ${c}`); 
    // console.log('a: ' + a + ', b: ' + b + ', c: ' + c); ANOTHER CODING CHOICE THAT WORKS.

    (function thirdFunction () {
      const a = 7; const c = 9;
      (function fourthFunction () {
        const a = 1; const c = 8;
      })()
    })()
  })()
})()