He was given to fanaticism in his political beliefs.

Answer: Option B

Limitations : a limiting rule or circumstance; a restriction.
Enthusiasm : intense and eager enjoyment, interest, or approval.
Falsehood : the state of being untrue.
Grounds : the solid surface of the earth.
Fanaticism : the quality of being fanatical; filled with excessive and single-minded zeal.

Synonym of Fanaticism is Enthusiasm