What is the reason for this decision?

A 34-year-old woman presented with palpitations, heat intolerance and a slight tremor. She was 9 weeks into her first pregnancy. She had not had any morning sickness.

On examination, her pulse was 100 beats per minute. She had a small uniform goitre but no tremor and no eye signs.

Investigations:

serum thyroid-stimulating hormone<0.01 mU/L (0.4C5.0)

serum free T442.0 pmol/L (10.0C22.0)

serum free T315.0 pmol/L (3.0C7.0)

anti-thyroid-stimulating hormone receptor

antibodies14 U/L (<7)

The decision was taken to treat her Graves’ disease with propylthiouracil (PTU) rather than carbimazole.

What is the reason for this decision?
A . concordance with PTU is greater
B . PTU does not cross the placenta
C . PTU is less associated with agranulocytosis
D . PTU is less associated with aplasia cutis
E . PTU is less associated with hepatitis