A package that has both child-resistant and non-child-resistant modes of operation. A container has an end with an open mouth surrounded by a container wall with a central axis and at least one first lock element extending radially outwardly from the wall. A closure includes an annular base wall having inner and outer peripheral edges. A cylindrical skirt extends from the outer peripheral edge of the base wall, and at least one second lock element is disposed on the skirt. A projection extends axially from the inner peripheral edge of the base wall in a direction opposite from the skirt. The projection has an annular sidewall spaced radially inwardly from the outer peripheral edge of the skirt. The closure is adapted to be secured to the container in a child-resistant mode of operation with the second lock element on the skirt releasably engaged with the first lock element on the container wall, and with the inner peripheral edge of the base wall in resilient engagement with the outer surface of the container wall to bias the lock elements in engagement with each other and to seal the package. The closure is adapted to be inverted and secured to the container in a non-child-resistant mode of operation with the annular sidewall of the projection received in plug-sealing engagement within the container mouth.