Given a dictionary named frequencies, which statement returns the value associated with the key $\text{'}$a$\text{'},$ or else $0$ if the key $\text{'}$a$\text{'}$ is absent$?$

a$.$ frequencies.get$(\text{'}$a$\text{'},0)$

b$.$ frequencies$[\text{'}$a$\text{'}]$ : $0$

c$.$ frequencies.get$(0,\text{'}$a$\text{'})$

d$.$ frequencies$[0]$ : $0$