It is C as to have freckles you have to have a dominant and recessive gene (can be worked out using a punnett square) as the child has 50% of not having freckles like his dad or 50% having freckles like his mom.
male genes(homozygous recessive)
f f
female F Ff Ff
genes
f ff ff
so ff is not having freckles and being homozygous recessive, or Ff having freckles and being heterozygous.
So the child is heterozygous so C
Maintenance of normal sinus rhythm
antidysrhytmic drugs are used to treat abnormal rhythm of the heart. Abnormal rhythm is usually due to the irregular electrical stimulation of the electrical activity of the heart. This can work by correcting the cardiac function there are four classes of this drugs such as Class I for sodium channels, Class II which are the beta blocker, Class III which are the drugs that prolong repolarization and Class IV which are the calcium channel blocker.
