The correct option is C an extended analogy
Here, central to the poem is the comparison that the poet makes between a mother-child relationship and her own relationship with something she has written. This takes up the entire poem so the poem can be called as an extended analogy. Analogy is defined as 'a thing which is comparable to something else in significant respects.' So, option A is the correct answer- other options do not appear to be as appropriate as A.