Which of the following are the effects of parathyroid hormone? 

a) Stimulates the process of dissolution or demineralisation of bones 

b) Decreases ${\mathrm{Ca}}^{2+}$ level in blood

c) Secretion of ${\mathrm{Ca}}^{2+}$ by renal tubules 

d) Regulation of basal metabolic rate

e) Increases the absorption of ${\mathrm{Ca}}^{2+}$ from digested food 

Choose the most appropriate answer from options given below.