The correct option is
C Proper Noun
Option A: Proper nouns name specific things or people. For example,
'Amy' is the name of a girl, 'America' is the name of a country, etc.
Also, proper nouns begin with a capital letter.
In the
given sentence, 'Trafalgar' (begins with a capital 'T') is the name of a
specific place in Spain. Hence it's a proper noun and option A is
correct.
Option B: Abstract nouns
refer to things that cannot be perceived through any of our senses
(touch, see, taste, smell, hear). They are emotions or states of being.
For example, 'happiness', intelligence', etc.
The noun 'Trafalgar' is a place and can be perceived through our senses. Hence it's not abstract.
Option
C: Collective nouns refer to a group of things or people and are
regarded as one single entity. The noun 'Trafalgar' does not refer to a
group.
Option D: The answer lies in option A.
Hence options B, C and D are incorrect.