In the sentence, identify the segment which contains the grammatical error.  Poverty is compounded by inflation which has reached extreme levels in the region, as demonstrated by consumer price indexes.

The grammatical error of the sentence is in option D. There are two plurals for some nouns, each with a different meaning. ‘Index’ is one of them. It has ‘indexes’ and ‘indices’ as its plurals. ‘Indexes’ mean (in a book or set of books) an alphabetical list of names, subjects, etc. with reference to the pages on which they are mentioned’ while ‘indices’ mean ‘pointers on an instrument, showing a quantity, a position on a scale etc. There is no mention of topics of a book or something thus, “indexes” is wrong here. Thus, replace “indexes” with “indices” to make the sentence grammatically correct. Correct sentence: Poverty is compounded by inflation which has reached extreme levels in the region, as demonstrated by consumer price indices.