Directions: In the sentence given below, four words have been highlighted which may be misspelt or inappropriate in their usage. Mark the erroneous word as the answer, and if all the words are correct, then choose option 'No error' as the answer.

According to financial analysts, the newly implemented policy requires meticuluos planning to ensure sustainable development.

The correct option is meticuluos.

Explanation:
Let us analyze the highlighted words in the given sentence:

1. policy: The spelling is correct. It means a course or principle of action adopted or proposed by a government, party, business, or individual.
2. meticuluos: This word is misspelt. The correct spelling is meticulous (ending in '-ous'). It means showing great attention to detail; very careful and precise.
3. sustainable: The spelling is correct. It means able to be maintained at a certain rate or level.
4. development: The spelling is correct. It means the process of developing or being developed.

Since meticuluos is misspelt, it is the erroneous word in the sentence.