Series Analysis:
The given number series is 450, 350, 230, ?, 10, -50. We need to find the missing term in the series.

Difference Analysis:
Let's analyze the differences between consecutive terms in the series to identify any pattern.

The difference between the first and the second term is 450 - 350 = 100.
The difference between the second and the third term is 350 - 230 = 120.
The difference between the third and the fourth term is 230 - x (missing term).
The difference between the fourth and the fifth term is x (missing term) - 10.
The difference between the fifth and the sixth term is 10 - (-50) = 60.

Pattern Analysis:
From the difference analysis, we can observe that the differences between consecutive terms are not following a consistent pattern. Therefore, we need to explore another approach to find the missing term.

Alternate Approach:
Let's try to find a pattern by considering the position of each term in the series.

The first term is at position 1, the second term is at position 2, the third term is at position 3, and so on.

Analyzing the positions of the terms, we can observe the following pattern:

The position of the first term is 1.
The position of the second term is 2.
The position of the third term is 3.
The position of the fourth term is 4.
The position of the fifth term is 5.
The position of the sixth term is 6.

Pattern Explanation:
The positions of the terms are decreasing by 1 with each term. Therefore, we can deduce that the missing term will be at position 4.

Calculating the Missing Term:
Since the position of the missing term is 4, we can calculate it using the formula:

Missing term = 4th term - (4th term - 3rd term) = 230 - (230 - 350) = 230 - (-120) = 230 + 120 = 350.

Therefore, the missing term in the series is 350.

Answer:
The missing term in the number series 450, 350, 230, ?, 10, -50 is 350. Option D is the correct answer.