The correct answer is fervor.
The correct answer is (B) Fervor; intense, tireless and persistent devotion to a cause or goal; eager and enthusiastic desire to advance a cause or render a particular service, ardor; dedication.
Zeal comes from Middle English zele, Greek zelos.
Examples of use:
- They recognize that he lacks the zeal required to lead a reform movement.
- Our players' zeal helped us to achieve our best season record ever.