6564. Elsie is seventy years old and a fanatical gardener.

✅ The correct answer is option C.
Crazy : mad, especially as manifested in wild or aggressive behaviour.

Fantastic : extraordinarily good or attractive.

Enthusiastic : having or showing intense and eager enjoyment, interest, or approval.

Obsessed : preoccupy or fill the mind of (someone) continually and to a troubling extent.

Fanatical : obsessively concerned with something.

Synonym of Fanatical is Enthusiastic