The correct answer is option D: 10 50.

Explanation:
To understand why option D is not entered correctly, we need to understand how formulas are typically entered in spreadsheets.

In a spreadsheet, formulas are entered in cells to perform calculations and return results. The basic syntax for a formula is as follows:

=operator(value1, value2)

Here, the equal sign (=) signifies that the cell contains a formula, the operator specifies the type of calculation to be performed, and the values are the operands or inputs for the calculation.

In option D, the formula entered is "10 50." This is not a valid formula because it does not follow the standard syntax. It is missing an operator between the two values.

Let's break down the other options to see why they are entered correctly:

Option A: =10 50
Here, the formula is "10 50." Similar to option D, it is missing an operator and is not entered correctly.

Option B: =B7*B1
This formula multiplies the value in cell B7 with the value in cell B1. It follows the correct syntax, with the multiplication operator (*) between the two cell references.

Option C: =B7 14
This formula subtracts the value 14 from the value in cell B7. It follows the correct syntax, with the subtraction operator (-) between the cell reference and the value.

In conclusion, the formula "10 50" in option D is not entered correctly because it lacks an operator between the two values.