Read the given statements and select the option that contains correct statements only
(a) Ecdysone is a steroid hormone that controls moulting in insects
(b) Artificial light, reduced sleep time disrupt the activity of pineal gland
(c) Fall in active vitamin-D levels directly stimulate the receptors present on cells of parathyroid gland to release parathormone
(d) The amino acid tryptophan is the precursor for the synthesis of melatonin and thyroxine
1. a and b
2. b and c
3. a and d
4. c and d