Final answer:
In Linear Programming models on spreadsheets, constant cells represent the LHS of constraints. Absolute, relative, and mixed cells differ in how they reference other cells when formulas are copied, but it is the constant cells that contain unchanging data pertinent to the LHS formulas in LP models.
Step-by-step explanation:
In the context of Linear Programming (LP) models within spreadsheet software, the type of cell that would represent the left-hand sides (LHS) of formulas typically depends on how the model is structured. However, given the options provided, constant cells are typically used to represent the LHS of constraints. In spreadsheet software, absolute cells (e.g., $A$1) have a fixed reference that doesn't change if the formula is copied to another cell, relative cells (e.g., A1) adjust their reference based on the position where they are copied, and mixed cells (e.g., $A1 or A$1) have both relative and absolute components. In LP models, constant cells contain data that does not change when formulas are replicated across rows or columns. Therefore, option (d) Constant cell would be the appropriate choice to represent fixed values in the LHS formulas of an LP model.