I assume you are doing the folllowing IMT assignment as the wording is identical- including the misspelling of clustered as 'clustured'
http://203.200.89.108/sis/downloads/assignment s/IMT-03.pdf
The assignment rules say "Write answers in your own words as far as possible and refrain from copying from the text books/handouts or asking for answers on interent forums.
I'm no expert but i would say:
1. A Priori segmentation
In a priori segmentation, the market is split according to pre-existing demographic criteria such as age, sex or social economic status. More sophisticated versions include lifestage (which combines information about age, presence of children and working status) and geodemographics such as Experian's Mosaic or CACI's Acorn classification systems where households are allocated to specific clusters on the basis of typical household make up and housing type.
A priori segments are easy to define and easy to target with advertising and media. For some sectors, for instance technology, there are such strong relationships between age and use, that a priori segments are all that are needed. However in other markets - for instance drinks, it is more difficult to use pre-existing variables for segmentation.
A priori segmentations are also the simplest segmentation to apply and use. A database can be flagged or sorted on the pre-existing data and that data used to drive sales and marketing campaigns.
However, although better than pure mass marketing, even the most sophisticated a priori systems are quite crude. In geodemographics there is the assumption that you buy or think the same way as your neighbour which is clearly not always the case.
Clustered- try this