The correct option is C Hamid exclaimed that it was a very fascinating flower.
When a sentence is changed from direct to indirect speech, the subject pronoun, verbs, and tense forms also change. (This is because the speech
is reported by someone else, and the tense of the direct speech goes one
tense back as it's spoken at a later time now.) The meaning of the sentence should not be changed.
An exclamatory sentence, when changed to reported speech, does not function as exclamatory anymore. It turns
into a declarative sentence.
So, the exclamatory words, along with the mark '!' change as well.
Option C: This contains the most suitable narration of direct speech.
'What' is changed to 'exclaimed that' and the sentence that follows is
changed to past tense.
When the direct speech is in the simple present tense (it is), the reported speech will change to its corresponding past tense (simple past) 'it was'. Hence C is the correct option.
Option A: This is not the correct form, because the words have not changed according to the indirect speech. Only the tense of the verb 'is' is changed to 'was'.
Option B does not bring out the meaning of the sentence conveyed by the exclamation. Hence B is incorrect.
Option D is incorrect because the answer lies in C.