This task is about writing a correct answer for the reading comprehension task. Based on the information provided in a given passage, you should identify the shortest continuous text span from the passage that serves as an answer to the given question. Avoid answers that are incorrect or provides incomplete justification for the question.

Passage: Red is the traditional color of warning and danger. In the Middle Ages, a red flag announced that the defenders of a town or castle would fight to defend it, and a red flag hoisted by a warship meant they would show no mercy to their enemy. In Britain, in the early days of motoring, motor cars had to follow a man with a red flag who would warn horse-drawn vehicles, before the Locomotives on Highways Act 1896 abolished this law. In automobile races, the red flag is raised if there is danger to the drivers. In international football, a player who has made a serious violation of the rules is shown a red penalty card and ejected from the game. Question: What is a football player shown before being ejected from a match?
a red penalty card

Passage: In 2010, a leaked cable revealed that Shell claims to have inserted staff into all the main ministries of the Nigerian government and know "everything that was being done in those ministries", according to Shell's top executive in Nigeria. The same executive also boasted that the Nigerian government had forgotten about the extent of Shell's infiltration. Documents released in 2009 (but not used in the court case) reveal that Shell regularly made payments to the Nigerian military in order to prevent protests. Question: A 2010 leaked communication revealed that Shell claimed to have inserted what into which entities?
staff into all the main ministries of the Nigerian government

Passage: An electromagnetic wave refractor in some aperture antennas is a component which due to its shape and position functions to selectively delay or advance portions of the electromagnetic wavefront passing through it. The refractor alters the spatial characteristics of the wave on one side relative to the other side. It can, for instance, bring the wave to a focus or alter the wave front in other ways, generally in order to maximize the directivity of the antenna system. This is the radio equivalent of an optical lens. Question: What is used to allow one to control the function of wave fronts moving through an antenna?

selectively delay