(A) Both (A) and (R) are true and (R) is the correct explanation of (A).
Banks require collateral as a guarantee for loans; those without collateral cannot provide it, so banks are unwilling to lend to such borrowers.
The textbook explicitly states that "absence of collateral is one of the major reasons which prevents the poor from getting bank loans." Thus R directly and correctly explains A, making option (A) the right choice. Remember: collateral is the key term linking both statements.