In the year 1960, which one of the following states officially became the 15th state of the Republic of India?

Option 1: Himachal Pradesh -> Became a full-fledged state only in 1971.

Option 2: Gujarat -> Formed on May 1, 1960, after bifurcation of Bombay State.

Option 3: Haryana -> Carved out of Punjab in 1966, not 1960.

Option 4: Odisha -> Already existed as a state since 1936/1947, not formed in 1960.

Hence, Option 2: Gujarat -> On May 1, 1960, the bilingual Bombay State was divided on linguistic lines into two states: Maharashtra (for Marathi speakers) and Gujarat (for Gujarati speakers). Gujarat thus became the 15th state of the Republic of India in 1960. -> correct