Arrange in ascending order:
1,234; 2,345; 6,784; 1,543
\[\begin{align}
  & \left( A \right)1,234;2,345;6,784;1,543 \\
 & \left( B \right)1,234;1,543;2,345;6,784 \\
 & \left( C \right)1,543;1,234;2,345;6,784 \\
 & \left( D \right)1,543;1,234;6,784;2,345 \\
\end{align}\]

Hint: To solve the given problem, we first need to know the meaning of ascending order. The ascending order of numbers is a special sequence in which the smallest number is written first and the largest number is written at last. The remaining numbers are then written in the algebraically increasing order. We will solve the given problem using this definition of ascending order.

Complete step by step solution:
The given numbers are 1,234; 2,345; 6,784; 1,543. Algebraically the smallest number from these four numbers is 1,234. Hence, the first number in the ascending order is 1,234. The number that is algebraically closest to this is 1,543, thus it is the second number in ascending order. Similarly, from this the number that should be at third position is 2,345. Finally, the number 6,784 that is largest is at the last position.
Using this the ascending order of the given numbers can be written as \[1,234;1,543;2,345;6,784\]. From the given options this matches with the option B.
Thus, the answer is option \[\left( B \right)1,234;1,543;2,345;6,784\].

So, the correct answer is “Option B”.

Note: We should also know about descending order of numbers. The descending order of numbers is a special sequence in which the largest number is written first and the smallest number is written at last. The remaining numbers are then written in the algebraically decreasing order. If we know the ascending order of the numbers, the descending order can be written simply by writing the sequence in the reverse order.