In which decade did Britain give up its policy of laissez faire and adopt a policy of ‘imperial preferences’ in its colonies

Q. In which decade did Britain give up its policy of laissez faire and adopt a policy of ‘imperial preferences’ in its colonies?

(a) 1850s

(b) 1870s

(c) 1890s

(d) 1930s

Ans: (d) 1930s