The correct answer is B. 6 digits.
A 16-bit word can store 2^16 = 65536 different values. A floating point number is stored in a 16-bit word as a sign bit, an exponent, and a significand. The sign bit indicates whether the number is positive or negative. The exponent is a 4-bit number that indicates the power of 2 to which the significand should be raised. The significand is a 12-bit number that represents the fractional part of the number.
The accuracy of a floating point number is determined by the number of digits that can be stored in the significand. A 12-bit significand can store 12 digits of precision. Therefore, the accuracy of a floating point number representable in two 16 bit words of a computer is approximately 6 digits.
Option A is incorrect because it states that the accuracy is 16 digits. This is not possible because a 16-bit word can only store 16 bits of information.
Option C is incorrect because it states that the accuracy is 4 digits. This is not possible because a 12-bit significand can store 12 digits of precision.
Option D is incorrect because it states that all of the above are correct. This is not possible because option A is incorrect and option C is incorrect.
Option E is correct because it states that none of the above are correct.