In each of the questions given below, four sentences are provided. One of the four sentences contains a grammatical error. Identify the sentence that contains the error. If all sentences are grammatically correct, select 'All are correct' as your choice.

The correct option containing the grammatical error is: "The container had a tear, which letting the flour to spill out."

Detailed Explanation:
Sentence 3 contains two distinct grammatical errors in its structure:

1. Incorrect Verb Form in Relative Clause: The relative pronoun "which" must be followed by a finite verb (such as "let" or "was letting") to form a proper relative clause, rather than the present participle "letting".
2. Incorrect Verb Pattern: The causative verb "let" is followed by an object and a bare infinitive (infinitive without "to"). Therefore, the correct construction is "let the flour spill out" rather than "letting the flour to spill out".

The grammatically correct version of the sentence is: "The container had a tear, which let the flour spill out."

Analysis of the remaining options:
• "Advocates value the project for its ability to raise national revenue." — Grammatically correct with proper subject-verb agreement and prepositional use.
• "The initial recipient of the IMF grant was Belgium back in 1950." — Grammatically correct in structure and tense.
• "Trauma during youth can lead to severe anxiety later in life." — Grammatically correct, properly using the modal verb "can" followed by the phrasal verb "lead to".