Introduction:
When discussing prospects for a job, it is commonly understood that individuals hope for opportunities or potential for growth and advancement within their career. The given sentence states that everyone desires a job with prospects _________ promotion, and the correct answer is 'of'. Let us explore the reasons behind this choice.

Using 'of' to express prospects:
In this context, the word 'prospects' refers to the likelihood or potential for promotion within a job. When we use 'prospects' in this manner, we typically follow it with the preposition 'of'. This is because 'of' is used to indicate possession or connection, and in this case, it signifies the connection between the job and the potential for promotion.

Examples:
To illustrate the usage of 'of' with prospects, consider the following examples:

1. "There are excellent prospects of promotion in this company."
2. "He has good prospects of advancing in his career."

In both of these examples, 'of' is used to establish the link between the prospects and the potential for advancement or promotion.

Alternative prepositions:
While 'of' is the most suitable preposition to use in this context, it is worth noting that there are other prepositions that can be used with 'prospects' depending on the intended meaning. For example:

1. 'For': This preposition can be used to express prospects for a particular outcome or result. For instance, "She has prospects for success in her new business venture."

2. 'In': This preposition can be used to describe prospects within a specific field or industry. For example, "The prospects in the technology sector are quite promising."

However, in the given sentence, where the focus is on prospects for promotion within a job, 'of' is the appropriate preposition to use.

Conclusion:
In conclusion, when discussing prospects for promotion within a job, the correct preposition to use is 'of'. This preposition establishes the connection between the job and the potential for advancement. It is essential to understand the appropriate usage of prepositions to ensure clear and effective communication in writing.