Which of the following derivations does a top-down parser use while parsing an input string? The input is assumed to be scanned in left to right order.
Leftmost derivation Top-down parsing (LL).
In top-down parsing, we just start with the start symbol and compare the right side of the different productions against the first piece of input to see which of the productions should be used.
A top-down parser is called LL parser because it parses the input from Left to right, and constructs a Leftmost derivation of the sentence.
Option A is correct