Exams

All locks are bangles + All bangles are cars = A + A = A
= All locks are cars => Some cars are locks.
Hence conclusion (a) follows.
All keys are locks + All locks are bangles = A + A = A
= All keys are bangles => some bangles are keys.
Hence conclusion (b) follows.
All keys are bangles + All bangles are cars = A + A = A
= All keys are cars => Some cars are keys.
Hence conclusion (C) follows.

Thus all a, b and c follows.

Bitcoin is the world's first cryptocurrency,    a    form    of electronic   cash.It   is   the    first decentralized digital  currency:  the system   was   designed   to   work without   acentral   bankor   single administrator.Bitcoins    are    sent from  user  to  user  on  the peer-to-peer bitcoin network directly, without the need for intermediaries.  These  transactions are verified by network nodes through cryptography and recorded in a public distributed ledger called a block chain. Bitcoin was invented by an unknown person or group of people   using   the   name Satoshi Nakamoto. Bitcoins are not recognised  as  a  legal  tender  by Reserve Bank of India.