The parts P, Q, R, and S of the following sentence have been jumbled. Choose the order that forms a coherent sentence: Georgian loyalists and rebel forces P: after a week of fighting Q: agreed to R: a ceasefire today S: in which 51 people were killed.

Introduction / Context:
This question tests your ability to arrange sentence parts logically to form a meaningful news style statement. The subject involves Georgian loyalists and rebel forces agreeing to a ceasefire. You must decide how to place the time phrase, the main action, and the descriptive clause about casualties in correct order so that the sentence reads smoothly and clearly.

Given Data / Assumptions:
The jumbled parts are:
- P: after a week of fighting
- Q: agreed to
- R: a ceasefire today
- S: in which 51 people were killed
The fixed beginning of the sentence is "Georgian loyalists and rebel forces".

Concept / Approach:
In news reporting, the natural pattern is subject followed by the main verb and its object, and then by time or additional descriptive clauses. The core action here is "agreed to a ceasefire today". The information about time and casualties "after a week of fighting in which 51 people were killed" logically follows this core. Therefore, we expect the order to be: subject + Q + R + P + S.

Step-by-Step Solution:
Step 1: Join the subject with the main verb phrase. "Georgian loyalists and rebel forces agreed to" comes from placing Q immediately after the subject. Step 2: Attach the direct object of the agreement. R gives "a ceasefire today", so "agreed to a ceasefire today" becomes the core statement. Step 3: Add the time frame of the fighting before the ceasefire. P adds "after a week of fighting". Step 4: Finally, specify what happened during that week. S adds "in which 51 people were killed". Step 5: The full sentence becomes "Georgian loyalists and rebel forces agreed to a ceasefire today after a week of fighting in which 51 people were killed."

Verification / Alternative check:
Check this against the answer choices. The sequence we derived is Q R P S, which corresponds to option D. Other orders either break the core verb object sequence or interrupt phrases that should be kept together. For example, Q P S R would yield "agreed to after a week of fighting in which 51 people were killed a ceasefire today", which is clearly ungrammatical.

Why Other Options Are Wrong:
- P Q R S: places "after a week of fighting" immediately after the subject, resulting in a clumsy structure and delaying the main verb.
- Q R S P: puts "in which 51 people were killed" before "after a week of fighting", which breaks the logical order of fight then casualties.
- Q P S R: separates "agreed to" from its direct object "a ceasefire today", which makes the sentence incoherent.

Common Pitfalls:
A common mistake in sentence arrangement questions is to focus only on meaning and ignore grammatical patterns like verb object order. Always identify the central verb phrase and keep the verb and its object together. After establishing the core sentence, place time expressions and relative clauses either at the beginning or end, whichever gives a more natural flow. In news style English, the action is usually stated early, with details added afterwards.

Final Answer:
The correct sequence is Q R P S, forming the sentence "Georgian loyalists and rebel forces agreed to a ceasefire today after a week of fighting in which 51 people were killed."