Scoring doesn't matter if you have no background in the subject, have poor preparation and generally dislike the subject. You'll never get a good score if you don't have an affinity with the subject.

Pick a subject based on:
(1) Your personal preference and background
(2) Overlapping of the syllabus with other subjects
(3) How short or extensive the syllabus is
(4) Past papers and the type of questions asked
(5) The amount of time you can give to a subject for preparation

As someone who has picked English Literature as optional and has an M.Phil in the subject, you don't just have to have read many novels, you need the ability to critically analyze a text, to argue and to present your arguments in a rational and understandable manner. Literature is not about producing a text's summary, but analyzing and producing critique.

I suggest you look at past papers and determine if you would be able to understand and solve questions. Also look at the length of syllabus and determine if you could cover it.

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"All I know is that I know nothing." - Socrates