Answer:
C). Under the tree sat my cat.
Explanation:
As per the standard rules, the correct order of the different parts of speech in a sentence is as follows;
'Sub. + auxiliary verb + main verb + adjective + adverb + preposition, etc. + object.'
The third sentence i.e. 'Under the tree sat my cat' follows an inverted subject-verb order as it does not follow the above sequence and thus, the meaning of the sentence is affected. Thus, the correct grammatical and lexical sentence would be;
'My Cat sat under the tree.'
