Apply the statement technique to define the real problem? Use assumptions?

Statement technique: The real problem is that sales have been declining for the past three quarters, leading to a decrease in revenue and profitability for the company.

Assumptions:
1. The decline in sales could be due to changes in consumer preferences or market trends.
2. There may be increased competition in the industry, leading to a loss of market share.
3. The company's marketing and sales strategies may not be effectively reaching target customers.
4. Economic factors such as a recession or downturn in the market could be impacting consumer spending.

You are a real estate analyst tasked with valuing residential properties in Debremarkos town. To assist in your valuation process, you decide to apply econometric techniques, specifically simple linear regression (SLR) and multiple linear regression (MLR).
A) Define SLR and MLR in the context of econometrics.
B) Explain how you would apply SLR to estimate the value of residential properties using a single predictor variable.
C) Describe the steps you would take to apply MLR in estimating property values, considering multiple predictor variables.
D) Discuss the limitations and potential challenges associated with the application of econometrics techniques, such as SLR and MLR, to real property valuation.