There are several examples of personification in the first stanza of "Song of the Sea." These include:
The sea "plays with the clouds" - this gives the sea human-like qualities of playfulness and perhaps even mischievousness.
The sea "mocks the skies" - this also gives the sea human-like qualities of teasing or taunting.
The sea "lies like a cradled creature" - this gives the sea a quality of being gentle and nurturing, like a baby being cradled.
Therefore, the correct answers are:
The sea "plays with the clouds"
The sea "mocks the skies"
The sea "like a cradled creature lies