What is the Ionian mode characterized by in terms of intervals?

The Ionian mode is recognized as the first mode of the major scale and is essentially the same as the major scale itself. Its interval structure is defined by the pattern of whole steps and half steps between the scale degrees.

In the Ionian mode, there are half steps specifically located between the third and fourth degrees and the seventh and eighth degrees (the root of the scale). This gives the Ionian mode its characteristic sound, which is bright and happy, as is typical of major scales.

The intervals in the Ionian mode are arranged as follows: whole step, whole step, half step, whole step, whole step, whole step, half step. This structure is distinct and helps to establish the unique sound and feel of the Ionian mode in music. Other options listed do not accurately represent the interval arrangement found in the Ionian mode, which is strictly adhered to the major scale's interval pattern.