The correct answer is: A. pdf
A probability density function (pdf) is a function that gives the probability of a continuous random variable taking on a value within a given interval. It is often represented by the letter $f$.
The probability mass function (pmf) is a function that gives the probability of a discrete random variable taking on a specific value. It is often represented by the letter $p$.
The cumulative distribution function (cdf) is a function that gives the probability that a continuous random variable will be less than or equal to a given value. It is often represented by the letter $F$.
The pmv is not a commonly used term. It may be referring to the probability mass function, but it is not clear from the context.
Therefore, the only function that is associated with a continuous random variable is the pdf.