Choose the alternative which can replace the word printed in italic bold without changing the meaning of the sentence
Elsa is seventy years old and a fanatical gardener.
a) crazy
b) fantastic
c) excessively enthusiastic
d) obsessed

Hint: The word ‘fanatical’ refers to ‘filled with excessive and single-minded zeal'. This word is used as an adjective in the given sentence and the adverb form of this word is ‘fanatically’.

Complete answer:
 In order to replace the italicized word without changing the meaning of the sentence, we need the synonym of the given word. A synonym is a word or phrase that means exactly or nearly the same as another word or phrase in the same language, for example, ‘shut’ is a synonym of ‘close’.

In the given sentence, the word ‘fanatical’ is used to describe the kind of gardener that Elsa is. It gives us essential information about her as a person.

Now, we know the meaning of the given word. Let’s look at the given options:

crazy - The word ‘crazy’ refers to ‘mad, especially as manifested in wild or aggressive behavior'. This word has a very different meaning to the given word. This is not the synonym of the given word as it would change the meaning of the sentence. This is not the required answer. So, this is an incorrect option.
fantastic - The word ‘fantastic’ refers to ‘extraordinarily good or attractive'. This word also has a different meaning to the given word. This is not the synonym of the given word as it would change the meaning of the sentence. This is not the required answer. So, this is an incorrect option.
excessively enthusiastic - The phrase ‘excessively enthusiastic’ refers to ‘having or showing an excessive degree of enthusiasm'. This phrase has the exact same meaning as the given word. This will help to retain the original meaning of the sentence. This is the required answer. So, this is the correct option.
obsessed - The word ‘obsessed’ refers to ‘preoccupied with or haunted by some idea, interest, etc'. This word does not have the exact same meaning as the given word. It will change the meaning of the sentence. This is not the required answer. So, this is an incorrect option.

Note:
Understand the meaning of the given sentence. Go through the options one by one and guess the meaning of each one. Choose the option with the exact same meaning to the given word, i.e. a synonym.