Final answer:
While the options do not directly indicate a neoconservative trend in jazz, Art Blakey's Jazz Messengers could be seen as preserving traditional jazz values. The founding of the Jazz Messengers (option b) is the closest answer, representing a traditionalist rather than neoconservative turn in jazz history.
Step-by-step explanation:
The question "Which of the following events marked the beginning of a neoconservative trend in jazz?" relates to the historical and cultural evolution of jazz music. While the options provided do not directly signify the beginning of a neoconservative trend in jazz, the Jazz Messengers led by Art Blakey represented traditional jazz values during a time of change and could metaphorically mark a conservative or neo-traditionalist approach to jazz. However, 'neoconservative' is typically a term used in a political context, not necessarily applied to jazz or its movements.
The closest answer to the given options that alludes to a conservative turn might be b. The founding of the Jazz Messengers by Art Blakey, as Art Blakey's formation of the Jazz Messengers in the early 1950s was viewed as a move to preserve and extend the hard-bop style of jazz, which was itself a reaction to the more commercial sounds prevalent in the 1950s. However, it's important to clarify that the term neoconservative is not typically used to describe trends in jazz. If anything, the Jazz Messengers' embrace of hard-bop was more traditionalist rather than neoconservative in a social and political sense.