(Generic pun involving the second word of "latus rectum")

Level pending

The latus rectum of a conic is the chord through the conic's focus and parallel to the conic's directrix.

What is the plural of "latus rectum"?

$$\textbf{1)}\text{ latus rectii}\\ \textbf{2)}\text{ latus rectums}\\ \textbf{3)}\text{ latii rectums}\\ \textbf{4)}\text{ latera recta}$$

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