The sequence 10101011, which indicates the actual start of the ...

[charchew]

The sequence 10101011, which indicates the actual start of the frame and
  enables the receiver to locate the first bit of the rest of the frame, is the ______.
 
  A. FCS B. SFD
 
  C. DA D. SA

Question 2

A seven-octet pattern of alternating 0s and 1s used by the receiver to establish
  bit synchronization is a ________.
 
  A. source address B. start frame delimiter
 
   C. preamble D. destination address

[ansleighelindsey]

Answer to Question 1

B

Answer to Question 2

C

[charchew]

Excellent

[Missbam101]

Thanks for the timely response, appreciate it