Question

What is a top-down parser?

(a) Begins by hypothesizing a sentence (the symbol S) and successively predicting lower level constituents until individual pre-terminal symbols are written

(b) Begins by hypothesizing a sentence (the symbol S) and successively predicting upper level constituents until individual pre-terminal symbols are written

(c) Begins by hypothesizing lower level constituents and successively predicting a sentence (the symbol S)

(d) Begins by hypothesizing upper level constituents and successively predicting a sentence (the symbol S)

I had been asked this question in an interview for internship.

Enquiry is from Communication in portion Communicating, Perceiving and Acting of Artificial Intelligence

Answer 1

Right choice is (a) Begins by hypothesizing a sentence (the symbol S) and successively predicting lower level constituents until individual pre-terminal symbols are written

To explain I would say: A top-down parser begins by hypothesizing a sentence (the symbol S) and successively predicting lower level constituents until individual pre-terminal symbols are written.