Which of the following property is not true for a random walk process?a. volatility clusteringb. nonstationaryc. strong memoryd. has a unit root

A random walk process has the following properties:

a. Volatility clustering: This is not a property of a random walk. Volatility clustering refers to the phenomenon when large changes tend to be followed by large changes, of either sign, and small changes tend to be followed by small changes. This is a characteristic of financial time series, not a random walk.

b. Nonstationary: This is true for a random walk. A nonstationary process has a statistical property, such as mean or variance, that changes over time.

c. Strong memory: This is not a property of a random walk. In a random walk, each step is independent of the previous ones.

d. Has a unit root: This is true for a random walk. A unit root is a feature of some stochastic processes that can cause problems in statistical inference involving time series models.

So, the properties that are not true for a random walk process are volatility clustering and strong memory.