In this section, you find a sentence, parts of which are underlined. For each underlined part, four `"words"//"phrases"` are listed below. Choose the `"word"//"phrase"` nearest in meaning to the underlined part and blacken the corresponding space on the Answer Sheet.
A scientist generally carries out his investigations `ul"empirically"`.

Options

A. intuitively
B. verbally
C. through written communication
D. by observation and experiment