A chi-squared test of independence is run to answer the research question.
Consider the output of the test below, and answer the questions:
Pearson's Chi-squared test
data: table(var1, var4)
X-squared 3.7029, df 3, p-value 0.2954
What is the null hypothesis? Choose one among the following options:

a. the age of tree felled at a specialty timber plantation is not distributed according to the given table of probabilities
b. the age of tree is associated with wood species
c. the age of tree and wood species are independent
d. the age of tree felled at a specialty timber plantation is distributed according to the given table of probabilities