Q4) A) What is the ADC0804 reference pin? B) Select the correct answer for each of the following 1) The total addressable memory size by 8086 is (a)64K (b)128k (c)1M (d)64M. 2) BIU stands for (a)Bus indication unit (b)Bus Interface Unit (c)Binary Interrupt Unit (d) Bus Interconnection unit. flags (a)16,5 (b)8,5 (c)16,7 (d)16,9. 4) The physical address is bits long and corresponds to the actual binary code output by the BIU on the address bus lines. (a)16 (b)20 (c)24 (d)32. C)Mention the types of serial communication. 3) Flags is a bit register containing.