To save y'all the trouble of clicking each MSDN link given in the solution, here are my condensations of the basic definitions....
Defines a date. Three bytes with a range of 0001-01-01 through 9999-12-31.
Defines a time of day. Optionally specify a precision for the fractions of a second. Three to five bytes depending on precision (0-7 digits for fraction of second).
Defines a date that is combined with a time of day that is based on 24-hour clock. datetime2 can be considered as an extension of the existing datetime type that has a larger date range (0001-01-01 through 9999-12-31), a larger default fractional precision, and optional user-specified precision (0-7 digits for fraction of second). Six to eight bytes depending on precision.
Defines a date that is combined with a time of a day that has time zone awareness and is based on a 24-hour clock. Similar to datetime2 with the addition of storing the offset from UTC from -14:00 to +14:00. Ten bytes.
And, for comparison...
Defines a date that is combined with a time of day with fractional seconds that is based on a 24-hour clock. Date range is January 1, 1753, through December 31, 9999. Time range is 00:00:00 through 23:59:59.997 rounded to increments of .000, .003, or .007 seconds. Eight bytes.