I think the Answer is B.
The writer (of the RC) begins by agreeing that though the author of literary work includes enough substance to indicate the intended meaning, These pointers might not always be enough to narrow down just one intended meaning as in a Map. A map is an exact communication of the intended information(Location of places and the distance between them etc.) whereas a piece of literary work might convey more than one meaning. (For example, in a piece of poetry, the poet might have particular meaning in mind and he uses descriptions, narrations and figures of speech-'signs and symbols'- in his poem; however the poetry can be interpreted differently by different readers.)

A) Here 'signs and symbols' implies the pointers to the intended meaning and not the intricacies of Literary work
B)is correct Ans
C) This is not talking about theories but the the meaning conveyed by the Literary work.
D) Comparison of the literary work to a map is not the subject of discussion. 'Map' is merely used as a metaphor for something conveying an exact intended meaning.
E) Again 'signs and symbol' refers to the Literary work and not about the theories.

Thanks Mr. Smith. I got your point but I am unable to paraphrase your logic ('signs and symbol' are not always be enough to narrow down just one intended meaning as in a Map) to the choice B, which says text guides the reader to some extent in decoding. The context of "text" has not been mentioned anywhere. What closely one can paraphrase is 'something' else too must guide reader to decode. Any idea how "text" came in get here ?

Though, one can get to the answer by elimination of other wrong choices.

refer to updated reply
Hope it helps