Find the part of the sentence that contains an error:

It was not only the scattering of administrative authority across multiple agencies (1)/ that weakened coordinated policy-making, but the rigidity built into intersecting compliance frameworks (2)/ which, though intended to preserve procedural independence, (3)/ end up stalling inter-departmental coordination completely. (4)

The correct answer is (4).

Step-by-Step Explanation:

Let's analyze the grammatical structure and tense consistency of the sentence across its four parts:

1. Part (1): "It was not only the scattering of administrative authority across multiple agencies..."
This part introduces the main clause in the past tense ("It was not only...").

2. Part (2): "...that weakened coordinated policy-making, but the rigidity built into intersecting compliance frameworks..."
This part maintains past tense consistency with the verb "weakened".

3. Part (3): "...which, though intended to preserve procedural independence,"
This non-restrictive relative clause provides additional context in a past/passive participle construction ("intended to...").

4. Part (4): "...end up stalling inter-departmental coordination completely."
There is a tense inconsistency error here. Since the entire event and its consequences are narrated in the past tense ("It was...", "weakened..."), the verb "end" should also be in the past tense form, i.e., "ended up stalling" instead of the present tense "end up stalling".

Therefore, the error lies in part (4).