IMAT 2013 Q47 [Organic Isomers]

Which of the following must be correct about organic isomers?

  1. They have the same molecular formulae.
  2. Their physical properties are very similar.
  3. They have different structural formulae.

A. 1 and 2 only
B. 1, 2 and 3
C. 2 and 3 only
D. 1 only
E. 1 and 3 only