Number Series:
The given number series is 587, 443, 343, 279, 243, ?

To find the pattern and determine the missing number, let's analyze the given series step by step.

Step 1:
If we look at the given series, we can observe a decreasing pattern in the numbers. Each subsequent number is smaller than the previous one.

587, 443, 343, 279, 243, ...

Step 2:
Let's calculate the difference between each pair of consecutive numbers to see if there is a consistent pattern.

443 - 587 = -144
343 - 443 = -100
279 - 343 = -64
243 - 279 = -36
...

Step 3:
By analyzing the differences, we can observe a consistent pattern. The differences are decreasing by 44, then 36, then 28, and so on.

Step 4:
To find the missing number in the series, we need to continue the pattern.
The next difference should be 20, obtained by subtracting 8 from the previous difference of 28.

Step 5:
Now, let's calculate the missing number by subtracting 20 from the last given number.

243 - 20 = 223

Therefore, the missing number in the given series is 223.

Step 6:
Let's check if option B, 227, is the correct answer.

227 is not the correct answer as it does not follow the established pattern of decreasing differences.

Step 7:
Let's check option C, 220.

220 is not the correct answer either as it does not follow the established pattern.

Step 8:
Finally, let's check option D, 200.

200 is the correct answer as it follows the established pattern of decreasing differences and is obtained by subtracting 20 from the last given number.

Therefore, the correct answer is option D, 200.