<prompt> Which of the following statements about warfarin group of oral anticoagulants is FALSE?They interfere with an early step in the synthesis of clotting factorsIrrespective of the dose administered, their anticoagulant effect has a latency of onset of 1-3 daysTheir dose is adjusted by repeated measurement of prothrombin timeThey are contraindicated during pregnancy  <response>: Activation of factor II, VII, IX and X are inhibited by warfarin group of oral anticoagulants in presence of vitamin K These anticoagulants do not affect the synthesis of these factors. 