How did political reform gradually expand suffrage and make british parliament more democratic during the the 1800s

The answer is:

Suffrage was extended to most men;

representation was made fairer by getting rid of rotten boroughs

; the House of Lords lost its veto.

All of the things above give the common people with a very large influence in the government. Before all this, the nobles could create whatever legislation that they please without any consequences.

After the parliament become more democratic, the members of government had to conform to the will of the people if they do not want to lose their position.

b is the answer i am assuming