Answer:
A - beta[0]
Explanation:
Beta[0] is the first element of the array, therefore automatically it is a valid element of beta. B and C are disqualified because you would not use single quotations when referring to an element. D is disqualified because the element starts at 0 (beta[0]) and has 50 elements declared, therefore it would end at 49, with beta[49] being the last element.
