Step 1: Understanding the Concept:
The question tests the knowledge of uncountable nouns. The word 'advice' is an uncountable noun, which means it does not have a plural form (advices) and cannot be used with the indefinite articles 'a' or 'an'.
Step 2: Detailed Explanation:
The original sentence is "He always gave me a valuable advice."
The error here is the use of the article 'a' before the uncountable noun 'advice'. To correct this, the article 'a' must be removed.
Let's analyze the options:
(i) "He always give me a valuable advice." - Incorrect. The tense is changed to present ('give') which doesn't fit with "always gave", and the incorrect article 'a' is still present.
(ii) "He always gives me a valuable advice." - Incorrect. The incorrect article 'a' is still present.
(iii) "He always gave me valuable advice." - Correct. The original past tense 'gave' is maintained, and the incorrect article 'a' has been removed.
(iv) "He always gives me valuable advice." - This sentence is grammatically correct in the simple present tense, but it changes the tense of the original sentence. Option (iii) is a more direct correction of the given sentence.
Step 3: Final Answer:
The correct sentence is He always gave me valuable advice.