Pacemaker potential occurs due to: (A) Opening of transient, rapid T-type Ca2+ channel, (B) Opening of K+ channel, (C) Closure of Ca2+ channel, (D) Closure of funny Na+  channel
Answer is A. Pacemaker potential occurs due to

Opening of slow type funny Na+ channel
Opening of transient, rapid T-type Ca2+ channel
Early closure of K+ channel