[amp_mcq option1=”12″ option2=”5″ option3=”8″ option4=”1″ correct=”option3″]
The answer is 5.
The missing number is the sum of the first two numbers in the sequence, minus the third number. In this case, the first two numbers are 1 and 2, and the third number is 3. Therefore, the missing number is $1 + 2 – 3 = 5$.
Option A is incorrect because 12 is not the sum of the first two numbers in the sequence.
Option B is incorrect because 5 is the sum of the first two numbers in the sequence.
Option C is incorrect because 8 is not the sum of the first two numbers in the sequence.
Option D is incorrect because 1 is not the sum of the first two numbers in the sequence.