Not to use an I voice, rather make it definite.
<span><em>Example of what not to do...</em>
</span>"I believe that India has is too overpopulated because of [...] and actions need to be taken swiftly."
<span><em>Example of what to do instead...</em>
</span>"India is overpopulated due to [...] and actions need to be taken swiftly."
King Arthur showed chivalry and honor above everything else which is what medieval Europe praised as highest values. He was always just and wise in his ruling which is another aspect that the Western civilization values.
A. is wrong because (could'nt) is not the proper way to write the contraction for 'could not' it should be 'couldn't', also there is no need for the apostrophe after the word, yours it already possessive without the apostrophe.
B. is wrong because 'couldnt' is not the correct way to write the contraction for 'could not', it's couldn't.
C. She couldn't remember which suitcase was your's. is wrong because you don't need the apostrophe in your's because it possessive is, yours.
The sentence that contains no errors is D. She couldn't remember which suitcase was yours.
Hope this helps. :)