Choose the correct option $:-$
$(a)$ First seven pairs of ribs are called true ribs.
$(b)$ Sternum is a large triangular bone that is situated at the ventral part of the thorax.
$(c)$ Scapula has a slightly elevated ridge called the spine which projects as a flat,expanded process called the acromion.
$(d)$ Below the acromion is a depression called the glenoid cavity which articulates with the head of the humerus.

• A
  only $a, b$ and $c$
• B
  only $a$ and $c$
• C
  only $b, c$ and $d$
• D
  Only $a$