The three wordsTATA Assets Rockare flashed such that the words individually are switched on at regular intervals of 4,7 and 9 seconds respectively and after they are switched on, the words are switched off after 2 sec, 4 sec and 5 sec respectively. If at time 't' all the words happened to switch off simultaneously, find the least time 't' which all three words will switch on simultaneously.

• A. 38 sec
• B. 94 sec
• C. 126 sec
• D. 252 sec