yes answer should be B) for 60 bytes of packet we have 40 bytes of data...and for sending 200 bytes we need 5 packet and each one need header of 20 hence total headers required 5*20=100 bytes of data..
BUT IN OPTIONS I THINK OVERHEAD SHOULD BE 80 not 100....because for 200 bytes ..if send as 1 packet we need 20 bytes of header....and for 60 bytes packet we need total 100 bytes of header ....hence actual overhead should be 100-20....i also given a solution...in which i have deducted 20 bytes at last step...so hope you get it..