According to the guidelines of good journalism, which of the following is correct:

A. It was estimated the car was traveling sixty-five miles per hour when it crashed into a tree.
B. It was estimated the car was traveling 65 mph when it crashed into a tree.
C. It was estimated the car was traveling 65 m.p.h. when it crashed into a tree.
D. It was estimated the car was traveling sixty-five mph when it crashed into a tree.

According to the guidelines of good journalism, option B is correct: "It was estimated the car was traveling 65 mph when it crashed into a tree."

In journalism, numbers are often written in numerals rather than spelled out, and abbreviations like "mph" are preferred over writing out "miles per hour." Additionally, it's unnecessary to include the word "estimated" multiple times, as the reader understands that this information is an estimate by the way it's presented.

According to the guidelines of good journalism, the correct option would be:

B. It was estimated the car was traveling 65 mph when it crashed into a tree.

When reporting numerical values like speed, it is recommended to use digits instead of spelled-out numbers, such as "65" instead of "sixty-five." Additionally, the unit of measurement for speed, in this case, miles per hour (mph), should be abbreviated without periods. So, combining these guidelines, option B is the correct format for stating the estimated speed in the sentence.

The correct option according to the guidelines of good journalism is:

B. It was estimated the car was traveling 65 mph when it crashed into a tree.

In journalism, it is preferable to use numerals instead of spelling out numbers, except for very low numbers or when starting a sentence. Also, the unit of measurement, in this case, "mph" for miles per hour, should be written without periods.