In the following sentence, a blank has been given. Select the option that best completes the sentence meaningfully: The big stone monument was the only __________ the lost traveller remembered.

Introduction / Context:
This question is a vocabulary based fill in the blank that tests your ability to choose the most contextually appropriate word. The sentence describes a lost traveller who remembers only one thing in the surroundings a big stone monument. The missing word must match this context and express the idea that the monument served as a point of reference or guidance for the traveller. Choosing the right noun here is about both meaning and typical collocation in English.

Given Data / Assumptions:

• Sentence: The big stone monument was the only __________ the lost traveller remembered.• Options: specimen, souvenir, piece, landmark.• The traveller is lost and uses memory of the monument to orient himself.• We assume a normal context of navigation or recalling locations.

Concept / Approach:
In geography and daily life, a landmark is a prominent object or structure that helps people recognise or navigate a place. Monuments, towers, temples, and bridges are typical landmarks. Thus, landmark is the natural word to use when talking about the only object that a lost traveller remembers as a reference point. The other options either refer to different concepts or do not fit how English normally describes such situations. Therefore, the conceptual link between monument and landmark guides us to the correct answer.

Step-by-Step Solution:
Step 1: Identify the key idea the traveller is lost and remembers only one thing that could guide him.Step 2: Recall the meaning of landmark an easily recognisable object or feature that helps people know where they are.Step 3: Insert landmark into the sentence: The big stone monument was the only landmark the lost traveller remembered. This sounds natural and meaningful.Step 4: Examine specimen. This refers to an example of something, often used in scientific contexts, and does not match the navigational sense here.Step 5: Examine souvenir. This is a memento or keepsake that someone carries away from a place, which does not fit the idea of a fixed structure guiding a lost person.Step 6: Examine piece. It is too vague and does not specifically relate to navigation or location.

Verification / Alternative check:
You can test the sentence with each option. The big stone monument was the only specimen the lost traveller remembered feels scientific and out of place. Using souvenir suggests that the traveller carried the monument, which is impossible. Piece is a generic word and fails to capture the function of the monument as a guide. Only landmark creates a coherent image of a large visible structure that the traveller can recognise and use to find his way.

Why Other Options Are Wrong:
specimen is commonly used for samples in biology, geology, or museums, not for objects used to navigate an area. souvenir is a small object bought or kept as a reminder of a trip, not a large fixed structure out in the landscape. piece can refer to any portion or item and gives no idea of recognisable location. None of these words align with the role of a monument in helping a lost traveller remember where he has been.

Common Pitfalls:
Some candidates may be tempted by souvenir simply because travellers and souvenirs are commonly associated in travel stories. However, the sentence clearly refers to something in the environment, not something the traveller carries. The best strategy is to focus on the function of the object in context here, a guide to place and direction rather than a keepsake.

Final Answer:
The word that best completes the sentence is landmark.