Which one of the following set of constraints represents the shaded region given below?

The graph shows a shaded region bounded by several lines. Each boundary line corresponds to a constraint that needs to be identified.

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The boundary lines visible in the graph are:

A vertical line at $x = 400$

A horizontal line at $y = 700$

A slanting line $x + y = 800$

Another slanting line $2x + y = 1000$

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For the vertical line at $x = 400$:

The shaded region is to the left of this line.

This gives the constraint $x \leq 400$

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For the horizontal line at $y = 700$:

The shaded region is below this line.

This gives the constraint $y \leq 700$

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For the line $x + y = 800$:

The shaded region is below this line.

This gives the constraint $x + y \leq 800$

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For the line $2x + y = 1000$:

The shaded region is below this line.

This gives the constraint $2x + y \leq 1000$

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The shaded region is in the first quadrant, which means:

$x \geq 0$

$y \geq 0$

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The complete set of constraints is:

$x + y \leq 800, 2x + y \leq 1000, x \leq 400, y \leq 700, x \geq 0, y \geq 0$

This matches Option 1.