Concept:In poetry, the name of a line depends on the number of metrical feet it contains.
The Greek prefix "hepta-" means seven.
Explanation:A metrical foot is the basic unit of rhythm in a line of poetry.
When a line contains seven feet, it is called heptametre.
Hexametre means six feet per line, so it is not correct here.
A septet is a stanza of seven lines, not a line with seven feet.
A triolet is a fixed French poetic form of eight lines, so it does not fit the description.
Therefore, seven metrical feet in a line of a stanza is known as heptametre.
Answer:C. heptametre