By which sutra multiplication can be performeda.     Nikhilamb.    Urdhva tiryagbhyamamc.     Paravartya yojyetad.    None of these

To determine which sutra can be used for multiplication, we can analyze the options.

1. Nikhilam: This sutra, which means "all from 9 and the last from 10," is primarily used for subtraction of large numbers but not specifically for multiplication.

2. Urdhva Tiryagbhyam: This sutra translates to "Vertically and Crosswise." It is specifically designed for performing multiplication of numbers, especially useful for multiplying numbers with multiple digits.

3. Paravartya Yojayet: This sutra is more focused on the context of division rather than multiplication.

4. None of these: This option would imply that none of the listed sutras are related to multiplication.

Conclusion

The correct answer is b. Urdhva Tiryagbhyam, as it is directly related to multiplication operations in Vedic mathematics. This method is versatile and can be applied for multiplying numbers of various digits effectively.