In churches where there are 'hangings' ~ not executions, we hasten to clarify; but rather, decorative fabric hangings on the front of the altar and perhaps such fittings as the lectern and/or pulpit ~ these may well be changed during the course of the liturgical year for reasons of visual variety and particular symbolism, along with any matching vestments for the clergy, such as the stole or chasuble.
ONE of the following statements is INACCURATE: which one?
Purple (or blue), as a rich and sombre colour, is associated with the seasons of Advent (the month or so prior to Christmas) and Lent (the six weeks or so prior to Easter)
Red is fairly obviously associated with blood (as in the Feast Days of martyrs) and the fire of Pentecost, and, by further extension from this, to such sacramental occasions as confirmation and ordination
White is used on Christmas Day and through the Epiphany season, probably for its association with innocence and purity (and in the northern hemisphere, seasonally with snow!)
Green is associated with Harvest Festival