Sentences of a paragraph are given below in jumbled order. Arrange the sentences in the correct order to form a meaningful and coherent paragraph.
A. In fact he began his career as a peon in a small firm.
B. Before he joined us as the accounts officer, he was a junior clerk.
C. He learnt typing, accounting and even graduated.
D. But he gradually improved his qualifications.

A

CDAB

B

BADC

C

CBAD

D

BCDA