Final answer:
Interior Designs Inc. uses an undifferentiated targeting strategy by employing a single marketing mix for their high-end, custom products, though they may also incorporate elements of a focused strategy.
Step-by-step explanation:
Interior Designs Inc. is most likely using an undifferentiated targeting strategy if they are selling expensive custom-made draperies, bedding, and accessories using a single marketing mix. An undifferentiated targeting strategy is one where a company decides to ignore market segment differences and go after the whole market with one offer. This is in contrast to a differentiated marketing strategy, where a company targets several market segments with a different offering for each. Given the high-end, custom nature of the products, Interior Designs Inc. may also be using aspects of a focused strategy if they specifically target a narrow market segment.