Arrange the following compounds in increasing order of boiling point. Propan - 1 - ol, butan - 1 - ol, butan - 2 - ol, pentan - 1 - ol (a) Propan-1-ol, butan-2-ol, butan - 1 - ol, pentan-1-o| (b) Propan-1-ol, butan - 1 - ol, butan-2-ol, pentan-1-ol (c) Propan-1-ol, butan-2-ol, butan-1-ol, pentan-1-ol (d) Propan-1-ol, butan-1-ol, butan-2-ol, pentan-1-ol