Read the given information carefully and answer the questions based on it: In a certain code language,

‘Several single port around’ is coded as ‘po xl yu vb’
‘Single event cost edition’ is coded as ‘rf zx vb wa’
‘Cost around public order’ is coded as ‘km po rf tf’
‘Public host winter edition’ is coded as ‘vc ur km zx’

If ‘several books’ is coded as ‘xl sa’ , then what will be the code for ‘port maintenance cost’?

To find the code for the phrase ‘port maintenance cost’, let us analyze the given coded sentences step-by-step by comparing common words and their corresponding codes:

1. Identify the codes for common words:
Comparing the first and second statements:
‘Several single port around’ = ‘po xl yu vb’
‘Single event cost edition’ = ‘rf zx vb wa’
Here, the common word is ‘single’ and the common code is ‘vb’. Therefore, we have:
$\text{single}=\text{vb}$

Comparing the first and third statements:
‘Several single port around’ = ‘po xl yu vb’
‘Cost around public order’ = ‘km po rf tf’
Here, the common word is ‘around’ and the common code is ‘po’. Therefore, we have:
$\text{around}=\text{po}$

Comparing the second and third statements:
‘Single event cost edition’ = ‘rf zx vb wa’
‘Cost around public order’ = ‘km po rf tf’
Here, the common word is ‘cost’ and the common code is ‘rf’. Therefore, we have:
$\text{cost}=\text{rf}$

Comparing the second and fourth statements:
‘Single event cost edition’ = ‘rf zx vb wa’
‘Public host winter edition’ = ‘vc ur km zx’
Here, the common word is ‘edition’ and the common code is ‘zx’. Therefore, we have:
$\text{edition}=\text{zx}$.

2. Decode the words in the first statement:
In the first statement: ‘Several single port around’ = ‘po xl yu vb’
We already know that $\text{single}=\text{vb}$ and $\text{around}=\text{po}$.
This leaves the remaining words {‘several’, ‘port’} to be matched with the remaining codes {‘xl’, ‘yu’}.

3. Use the conditional information to identify ‘port’:
We are given that ‘several books’ is coded as ‘xl sa’.
Since ‘several’ must be either ‘xl’ or ‘yu’ from our previous step, this matching confirms that:
$\text{several}=\text{xl}$
Consequently, the code for ‘port’ must be ‘yu’:
$\text{port}=\text{yu}$.

4. Determine the code for ‘port maintenance cost’:
- The code for ‘port’ is ‘yu’.
- The code for ‘cost’ is ‘rf’.
- The word ‘maintenance’ is a new word that does not appear in any of the original sentences. Therefore, its code must be a new code that has not been used yet.
Looking at the options, the combination that contains both ‘yu’ and ‘rf’, along with a new code ‘nh’ (which is not used in any of the given statements), is ‘yu nh rf’.

Therefore, the correct answer is yu nh rf.