If one strand of a DNA has the sequence ATGCTTCA, sequence of the bases in complementary strand is:

We need to find the complementary strand for the DNA sequence ATGCTTCA. In DNA, the complementary base pairs are $$A \leftrightarrow T$$ (Adenine pairs with Thymine) and $$G \leftrightarrow C$$ (Guanine pairs with Cytosine).

For the given strand oriented 5' to 3' as A - T - G - C - T - T - C - A, each base pairs respectively to T - A - C - G - A - A - G - T. Reading this complementary strand from 3' to 5' yields TACGAAGT.

The correct answer is Option B) TACGAAGT.