GATE Computer Science (CS) 2020 Solved Papers

Eliminate the options.
--Option (A) is incorrect, it forces the string to start with 1, we cannot generate strings like 01, 0111, ….
-- Option (C) is incorrect, it generates string ending with 1, so cannot generate strings like 10, 1110
-- Option (D), not always generates strings with odd 1’s as it can generate 110.
-- Options (B), is correct, as it can generate all the string with odd number of 1’s.