Which phrase best describes the British government during the 19th century?
A. A nationalist empire attempting to unify all English-speaking territories
B. A constitutional monarchy with elected officials holding most political power
C. A liberal democracy that allowed all men and women to participate in politics.
D. A military dictatorship established after a nationalist revolution failed

The phrase that best describes British at the time is:

B. A constitutional monarchy with elected officials holding most political power

Explanation:

By the time of the 19th century Britain had taken a lot of the power of the monarchy away from them due to the constant and slow power struggle between the parliament and the  ruler.

By the time of Queen Victoria the prime minster of the nation was a s powerful or more but in name the Queen remained on top and was a big presence on the world stage.

This is why the place was more of a constitutional monarchy than anything else.