<prompt>  Local anaesthetic injectionsA fail, usually because the anaesthetic solution is out of date B followed by collapse is usually because of allergy to one of the constituents C followed by trismus after the effect of inferior dental local anaesthetic block has subsided usually indicates trauma in the region of the medial pterygoid muscle andor a haematoma D except for local infiltrations should be avoided in patients with haemophiliaAB is true and CD are falseAB are false and CD are trueAC are true and BD are falseAC are false an BD are true 