Correct Answer: 40

Solution : In a column, find the square of the first number to get the second number and then multiply the first number by consecutive natural numbers(starting from 3) to get the third number.

In the first column: 6 ² = 36 and 6 × 3 = 18
In the second column: 7 ² = 49 and 7 × 4 = 28
Similarly, in the third column: 8 ² = 64 and 8 × 5 = 40

So, 40 is the missing number in the given figure. Hence, the fourth option is correct.